Liquid crystalline filter dyes for imaging elements

ABSTRACT

This invention comprises dispersion comprising a solvent having dispersed therein a liquid-crystal forming dye of structural Formula I: 
     
       
         [D-(X) m ]-(Y) n   
       
     
     wherein: 
     D is a light-absorbing chromophore other than a cyanine dye or a barbituric acid oxonol dye; 
     each Y contains an ionic or a nonionic solubilizing substituent or a group with a pKa value of less than 4 in water; 
     each X is a nonionic substituent; 
     n is 0 to 10; 
     m is 0-10; and 
     the resulting dye forms a liquid-crystalline phase in solvent. 
     The dispersion is particularly useful in imaging and photographic elements.

FIELD OF THE INVENTION

This invention relates to a dispersion of a dye in a solvent wherein thedye forms a lyotropic liquid crystalline phase, a method for preparingsaid dispersions, an imaging element containing said dispersion and aphotographic element containing said dispersion.

BACKGROUND OF THE INVENTION

Radiation-sensitive materials, including light-sensitive materials, suchas photographic materials, may utilize filter dyes for a variety ofpurposes. Filter dyes may be used to adjust the speed of aradiation-sensitive layer; they may be used as absorber dyes to increaseimage sharpness of a radiation-sensitive layer; they may be used asantihalation dyes to reduce halation; they may be used to reduce theamount or intensity of radiation from reaching one or moreradiation-sensitive layers, and they may also be used to preventradiation of a specific wavelength or range of wavelengths from reachingone or more of the radiation-sensitive layers in a radiation-sensitiveelement. For each of these uses, the filter dye(s) may be located in anynumber of layers of a radiation-sensitive element, depending on thespecific requirements of the element and the dye, and on the manner inwhich the element is to be exposed. The amount of filter dyes usedvaries widely, but they are preferably present in amounts sufficient toalter in some way the response of the element to radiation. Filter dyesmay be located in a layer above a radiation-sensitive layer, in aradiation-sensitive layer, in a layer below a radiation-sensitive layer,or in a layer on the opposite side of the support from aradiation-sensitive layer.

Photographic materials often contain layers sensitized to differentregions of the spectrum, such as red, blue, green, ultraviolet,infrared, X-ray, to name a few. A typical color photographic elementcontains a layer sensitized to each of the three primary regions of thevisible spectrum, i.e., blue, green, and red. Silver halide used inthese materials has an intrinsic sensitivity to blue light. Increasedsensitivity to blue light, along with sensitivity to green light or redlight, is imparted through the use of various sensitizing dyes adsorbedto the silver halide grains. Sensitized silver halide retains itsintrinsic sensitivity to blue light.

There are numerous applications for which filtration or absorbance ofvery specific regions of light are highly desirable. Some of theseapplications, such as yellow filter dyes and magenta trimmer dyes,require non-diffusing dyes which may be coated in a layer-specificmanner to prevent specific wavelengths of light from reaching specificlayers of the film during exposure. These dyes must have sharp-cuttingedges on the bathochromic (long-wavelength) side of the absorbanceenvelope to prevent light punch through without adversely affecting thespeed of the underlying eraulsions. In other applications, it isdesirable to allow passage of light below a certain wavelength. In thesecases it is desirable to have a dye which is very sharp-cutting on thehypsochromic (short-wavelength) edge of the absorbance envelope.Depending on the location of these filter layers relative to thesensitized silver halide emulsion layers, it would also be desirable tohave non-diffusing, layer-specific filter dyes with absorption spectrawhich are sharp-cutting on the hypsochromic edge as well as thebathochromic edge. Such dyes are sometimes known as “finger filters”.Preferably these dyes should exhibit high extinction coefficients,narrow half bandwidths and sharp cutting hypsochromic and bathochromicabsorption envelopes when incorporated into imaging elements includingphotographic elements. Typically, to achieve these properties, isotropicsolutions of dyes have been incorporated. Dyes introduced by thismethod, however, often wander into adjacent layers causing problems suchas speed loss or stain, and cannot be coated in a layer-specific mannerwithout the use of mordants. Solubilized dyes may be mordanted toprevent wandering through adjacent layers. While the use of polymericmordants can prevent dye wandering, such mordants aggravate the stainproblem encountered when the dye remains in the element throughprocessing.

Dyes with a high extinction coefficient allow maximum light absorptionusing a minimum amount of dye. Lower requisite dye laydown reduces thecost of light filtration and produces fewer processing by-products.Lower dye laydowns may also result in reduced dye stain in shortduration processes.

Finger filters such as described above are highly desirable for otheruses such as protecting silver halide sensitized emulsions from exposureby safelights. Such dyes must have absorbance spectra with highextinction coefficients and narrow half bandwidths, and sharp cuttingabsorbance envelopes to efficiently absorb light in the narrowsafelight-emitting region without adversely affecting the speed of thesensitized silver halide emulsions. This affords protection for thesensitized emulsion from exposure by light in the safelight's spectralregion. Useful absorbance maxima for safelight dyes include, but are notrestricted to 490-510 nm and 590-610 nm.

Similar properties are required for infrared absorbing filter dyes.Laser-exposed radiation-sensitive elements require high efficiency lightabsorbance at the wavelength of laser emission. Unwanted absorbance frombroadly absorbing dyes reduces the efficiency of light capture at thelaser emission wavelength, and requires the use of larger amounts of dyeto adequately cover the desired spectral region. In photographicelements, unwanted absorbance may also cause speed losses in adjacentsilver halide sensitized layers if the photographic element has multiplesensitized layers present. Useful finger filter absorbance maxima forabsorbing laser and phosphor emissions include but are not restricted to950 nm, 880 nm, 830 nm, 790 nm, 633 nm, 670 nm, 545 nm and 488 nm.

In some radiation sensitive elements, including dry process imagingfilms, it is necessary to provide light filtration or antihalation atdeep cyan and infrared wavelengths. Typically such protection has beenachieved using water or solvent soluble dyes or milled solid particledyes. Typically, water-soluble dyes forming isotropic solutions canprovide relatively sharp, high extinction absorbance, but are prone tointerlayer wandering.

One common use for filter dyes is in silver halide light sensitivephotographic elements. If, prior to processing, blue light reaches alayer containing silver halide which has been sensitized to a region ofthe spectrum other than blue, the silver halide grains exposed to theblue light, by virtue of their intrinsic sensitivity to blue light,would be rendered developable. This would result in a false rendition ofthe image information being recorded in the photographic element. It istherefore a common practice to include in the photographic element amaterial that filters blue light. This blue-absorbing material can belocated anywhere in the element where it is desirable to filter bluelight. In a color photographic element that has layers sensitized toeach of the primary colors, it is common to have the blue-sensitizedlayer closest to the exposure source and to interpose a blue-absorbing,or yellow filter layer between the blue-sensitized layer and the green-and red-sensitized layers.

Another common use for filter dyes is to filter or trim portions of theUV, visible or infrared spectral regions to prevent unwanted wavelengthsof light from reaching sensitized emulsions. Just as yellow filter dyesprevent false color rendition from the exposure of emulsions sensitizedto a region of the spectrum other than blue, filter dyes absorbing inthe UV, magenta, cyan and infrared spectral regions can prevent falsecolor rendition by shielding sensitized emulsion layers from exposure tospecific wavelength regions. One application of this strategy is the useof green-absorbing magenta trimmer dyes. In one type of typical colorphotographic element containing a layer sensitized to each of the threeprimary regions of the visible spectrum, i.e., blue, green, and red, thegreen-sensitized layer is coated above the red-sensitized layer andbelow the blue-sensitized layer. Depending on the chosen spectralsensitivity maxima for the sensitized silver halide layers, there may bea region of overlap between the spectral sensitivities of the green andred emulsions. Under such circumstances, green light which is notabsorbed by the green-sensitive emulsion can punch through to the redsensitive emulsion and be absorbed by the leading edge of the redspectral sensitizing dye. This crosstalk between the green and redemulsions results in false color rendition. It would, therefore, behighly desirable to find a green-absorbing filter dye which uponincorporation into a photographic element would absorb strongly aroundI-he spectral maximum of the green-sensitized emulsion, and possess asharp cutting bathochromic absorbance such that there is no appreciableabsorbance just bathochromic to its absorbance maximum. A sharp-cuttingbathochromic edge on a filter or trimmer dye enables excellent colorreproduction with minimum speed loss by absorbing light efficiently upto its absorbance maximum, but very little if any just past itsabsorbance maximum. For example, a magenta trimmer dye (green absorber)which is only moderately sharp-cutting on the bathochromic edge mayfunction adequately as a filter dye, but its unwanted absorbance in thered region past its λ_(max) will rob the red-sensitive emulsion coatedbelow it of red light and hence speed. Though the position of optimalabsorption maximum for a magenta trimmer dye will vary depending on thephotographic element being constructed, it is particularly desirable inone type of typical color photographic element containing a layersensitized to each of the three primary regions of the visible spectrum,i.e., blue, green, and red, that a magenta trimmer dye absorb stronglyat about 550 nm, and possess a sharp cutting bathochromic absorbancesuch that there is no appreciable absorbance above about 550 nm.Therefore it would be desirable to provide a filter dye for use inphotographic elements that possesses high requisite absorbance in thegreen region of the spectrum below about 550 nm, but little or noabsorbance above about 550 nm, and furthermore does not suffer fromincubative or post process stain problems, and furthermore is not proneto migration in the coated film, but is fully removed upon processing.

One method used to incorporate solvent or water-soluble filter dyes intophotographic film element layers is to add them as aqueous or alcoholicisotropic solutions. Dyes introduced by this method are generally highlymobile and rapidly diffusing and often wander into other layers of theelement, usually with deleterious results. While the use of polymericmordants can prevent dye wandering, such mordants aggravate the stainproblem encountered when the dye remains in the element throughprocessing.

Filter dyes have also been prepared as conventional dispersions inaqueous gelatin using standard colloid milling or homogenization methodsor as loaded latices. More recently, ball-milling, sand-milling,media-milling and related methods of producing fine-particle-sizeslurries and suspensions of solid filter dyes have become standard toolsfor producing slurries and dispersions that can readily be used inphotographic melt formulations. Solid particle filter dyes introduced asdispersions, when coated at sufficiently low pH, can eliminate problemsassociated with dye wandering. However, solvent-insoluble solid particlefilter dyes (pigments) provide relatively low absorption coefficients,requiring that an excessive amount of dye be coated. In addition, it isvery difficult to find classes of solid particle dispersion dyes whichconsistently yield useful, sharp-cutting bathochromic or hysochromicspectral features due to their microcrystalline nature. In fact the hueof a microcrystalline dye is highly unpredictable and often variestremendously between similar analogs. In addition many solid particledyes are not robust under keeping conditions of high heat and humidityexperienced in melting and coating operations. Under such conditions,microcrystals of dye can undergo ripening, resulting in a lower opticaldensity post incubation. In addition, the time and expense involved inpreparing serviceable solid particle filter dye dispersions by millingtechniques are a deterrent to their use, especially in large volumeapplications. It is therefore desirable to provide dye dispersions thatdo not necessarily require mechanical milling before use and that do notwander but that wash out easily during processing leaving little or noresidual stain. It is also desirable that such filter dye dispersionsprovide high light absorption efficiencies with sharp-cutting absorbancepeaks. One method of obtaining these desirable dye features in solidparticle dispersions of oxonol filter dyes was described by Texter (U.S.Pat. No. 5,274,109, U.S. Pat. No. 5,326,687 and U.S. Pat. No.5,624,467). Texter describes a process by which pyrazolone oxonol dyesare micro precipitated under strictly controlled pH conditions toproduce absorbance spectra which are narrow, bathochromic and sharpcutting on the long wavelength side relative to their correspondingmilled solid particle dispersions. This technique, however, isimpractical for large volume applications.

A specific class of dyes, barbituric acid oxonol dyes, have beendisclosed in commonly assigned copending U.S. application Ser. No.08/565,480 filed Nov. 30, 1995, the entire disclosures of which areincorporated herein by reference, and U.S. Pat. No. 5,766,834 to possesssharp-cutting spectral properties when incorporated into gelatincoatings; however no reference is made to suggest that other filter dyeclasses might possess these useful spectral features. Further, thespectral features; of these dyes are limited to a few specificwavelength ranges, and the hue of these sharp-cutting dyes are nottunable over a large useful range.

It would be very useful if dye materials were available that werenon-wandering, like solid particle dispersions, but were additionallynarrowly absorbing and sharp-cutting in spectral features, like fullysolvent-soluble dyes, and were additionally available at a wide varietyof absorbance maxima useful in imaging elements.

Problem to be Solved by the Invention

It is therefore desirable to have a dye, especially a filter dye, whichhas a high extinction coefficient, a narrow halfbandwidth, and is sharpcutting on the bathochromic and/or hypsochromic edge, and even morepreferably on both the hypsochromic and bathochromic edges. For dyesused in photographic elements, it is additionally desirable that the dyeis capable of being substantially completely removed or renderedcolorless on process of an exposed radiation-sensitive elementcomprising said dye. It is also desirable that the coated dye be robustin its spectral and physical properties and not prone to migrationwithin the imaging element. It is also desirable to have a method forpreparing a dispersion of a filter dye that is suitable for high-volumemanufacture.

SUMMARY OF THE INVENTION

It has now been discovered that dyes from a broad range of classes maybe functionalized with certain substituents and solubilizing groups, anddispersed in hydrophilic colloids to form lyotropic (solvent-induced)liquid-crystalline dye phases (mesophases). These mesophase-forming dyespossess unique and useful properties superior to those of conventionalwater or solvent-soluble dyes or solvent-insoluble solid particle dyeswith respect to hue, spectral shape, immobility, robustness and processremovability. Additionally it has been discovered that for a given dyeclass, one skilled in the art can optimize dye analogs such that theypossess an inherent propensity to form stable liquid-crystalline phasesrather than microcrystalline (solid) or isotropic (e.g. solution) phaseswhen dispersed in solvents, including hydrophilic colloids such asaqueous gelatin. Additionally it has been discovered that modificationsin the properties of the hydrophilic colloid dye dispersion, such asionic strength, temperature and pH can improve a given dye's propensityto form a stable liquid-crystalline phase. Additionally it has beendiscovered that the advantageous spectral and physical properties of thedye liquid crystalline phases formed in the wet hydrophilic colloid(e.g. aqueous gelatin) are largely retained in the dried-down(evaporated) gelatin coatings of an imaging) element.

This invention relates specifically to amphiphilic dyes, especiallyfilter dyes in photographic elements which are capable of formingpractically useful lyotropic liquid-crystalline phases, particularlydyes from the polymethine classes. However, it is anticipated thatliquid crystal formation is not necessarily restricted to theseparticular dye classes nor specific dye structures. This technology mayalso be applied to any novel dye structure with potentially usefulphotographic filter properties. It is understood that the degree ofamphophilicity to be imparted to a particular dye chromophore by theincorporation of said solubilizing groups will vary from chromophore tochromophore and from dye class to dye class.

Liquid-crystalline filter dyes afford a host of benefits overconventional state-of-the-art solid particle(microcrystalline)-incorporated dyes or water-soluble (isotropicsolution) filter dyes, for photographic imaging applications. Moreover,they provide a combination of spectral and physical properties that isvirtually unachievable using either water-soluble or solid particledyes. The following beneficial spectral and physical properties areinherent to the liquid-crystalline form of the dye. For example, dyesdispersed in a lyotropic liquid-crystalline form exhibit slow collectivemolecular diffusion (orders of magnitude slower than dye isotropicsolution species) affording good layer specificity and immobility, like(microcrystalline) solid particle dyes and unlike unmordanted isotropicsolution dyes. Dyes dispersed in a lyotropic liquid-crystalline formexhibit significantly higher extinction coefficients than(microcrystalline) solid particle dyes dispersed at equivalent wetlaydowns (concentrations). Dyes dispersed in a lyotropicliquid-crystalline form show processing washout and bleaching ratescomparable to, but usually much better than, conventional(microcrystalline) solid particle dyes. Lyotropic liquid-crystalline dyephases are more easily, rapidly and reproducibly formulated than(microcrystalline) solid particle dye phases. Dyes dispersed in alyotropic liquid-crystalline form, (especially the smectic mesophaseform), often exhibit sharper-cutting, more intense spectral absorptionfeatures than their (microcrystalline) solid particle counterparts,making them particularly useful as photographic finger-filters. Dyesdispersed in a lyotropic liquid-crystalline form often exhibitcharacteristic bathochromically-shifted excitonic absorption J-bands(sharp, narrow and intense), possessing (long-wavelength) sharp-cuttingspectral features, making them particularly useful for many photographicfinger-filter applications. So-called J-band (J-aggregate) spectra arenot readily afforded by (microcrystalline) solid particle dyes. Dyesdispersed in a lyotropic liquid-crystalline form may also exhibitpractically useful hypsochromically-shifted H-band absorption spectra,with (short-wavelength) sharp-cutting spectral features. Dyes dispersedin a lyotropic liquid-crystalline state may also exhibit little or nospectral shift compared with the dye's isotropic solution absorbancestate, yet still retain the characteristic immobility of the liquidcrystalline phase. The essentially “immobile” lyotropicliquid-crystalline form (phase) of the preferred amphiphilic filterdyes, exhibiting characteristic and practically useful J-band and H-bandabsorption spectra, are quite distinct, easily identifiable and readilydistinguishable from non-liquid-crystalline (isotropic)rapidly-diffusing dye phases which occasionally exhibit similarabsorption spectra. Dyes dispersed in a lyotropic liquid-crystallinestate in aqueous, or those dyes passing through a transitory mesophaseupon the drying of aqueous gelatin layers, usually retain the usefulspectral and physical properties associated with the mesophase in theevaporated (dried-down)state. Dyes initially dispersed as a lyotropicliquid-crystalline form often exhibit good incubation stability inevaporated gelatin layers.

This invention comprises a very broad collection of dye classes whichcan form lyotropic liquid crystals when selectively functionalized asdescribed below. This disclosure further teaches one skilled in the arthow to find liquid-crystalline members of a given dye class; it furtherincludes test protocol for determining the presence of a dye mesophase(i.e. liquid crystal phase), and shows the superior features dye liquidcrystals possess compared with solid particle dyes or solvent-soluble(solution) dyes. This invention further demonstrates the advantages ofdye mesophase properties in imaging elements, especially photographicelements.

One aspect of this invention comprises a filter dye which when dispersedin a solvent, especially water or a hydrophilic colloid such as aqueousgelatin, forms a liquid-crystalline phase.

Another aspect of this invention comprises a filter dye which whendispersed in a solvent or a hydrophilic colloid such as aqueous gelatin,forms a smectic liquid-crystalline phase.

Another aspect of this invention comprises a filter dye which whendispersed in a solvent or a hydrophilic colloid such as aqueous gelatin,forms a nematic or hexagonal liquid-crystalline phase.

Another aspect of the invention comprises a dye lyotropicliquid-crystalline which exhibits a spectral absorbance maximumbathochromically or hypsochromically shifted, and exhibits an unusuallyhigh extinction coefficient and an exceptionally narrow halfbandwidthrelative to its isotropic monomeric solution state.

Another aspect of the invention comprises a dye lyotropicliquid-crystalline phase which possesses a spectral absorbance envelopewith an extinction coefficient and halfbandwidth similar to itsisotropic monomeric solution state.

Another aspect of this invention comprises a filter dye which whendispersed in a hydrophilic colloid such as aqueous gelatin to form aliquid-crystalline phase, possesses a narrow spectral absorption bandexhibiting an especially sharp-cutting short or long wavelength edge.

Another aspect of this invention comprises a filter dye which whendispersed in a hydrophilic colloid such as aqueous gelatin to form aliquid-crystalline phase, possesses a narrow spectral absorption bandexhibiting especially sharp-cutting short and long wavelength edges.

Another aspect of this invention comprises a filter dye which whendispersed in a hydrophilic colloid such as aqueous gelatin to form aliquid-crystalline phase, exhibits low dye diffusibility and interlayerwandering.

Another aspect of this invention comprises a direct gelatin dispersionmethod allowing easy, inexpensive, rapid and reproducible incorporationof the inventive dyes in the liquid-crystalline state, with alldesirable properties intact, into imaging elements, especiallyphotographic elements without recourse to milling techniques.

Another aspect of this invention comprises a filter dye which whendispersed in a hydrophilic colloid such as aqueous gelatin to form aliquid-crystalline phase exhibits excellent stability at hightemperature and humidity conditions.

Another aspect of this invention comprises a filter dye which whendispersed in a wet hydrophilic colloid such as aqueous gelatin to form aliquid crystalline phase retains all of the desirable physical andspectral properties once the coated imaging element is dried-down(evaporated).

Another aspect of the invention comprises a silver halideradiation-sensitive material containing at least one dye in theliquid-crystalline state, dispersed in a hydrophilic colloid layer,which is decolorized by photographic processing and which causes nodeleterious effects on the silver halide photographic emulsions beforeor after processing.

A further aspect of the invention comprises a silver halideradiation-sensitive material in which a hydrophilic colloid layer isdyed and exhibits excellent decolorizing properties upon photographicprocessing.

Yet another aspect of the invention comprises a silver halideradiation-sensitive material in which a hydrophilic colloid layer isdyed and exhibits high absorbance in a portion of the spectral region atits absorbance maximum, but possesses comparatively little absorbancearound 20 nm above its absorbance maximum.

Yet another aspect of the invention comprises a silver halideradiation-sensitive material in which a hydrophilic colloid layer isdyed and exhibits high absorbance in a portion of the spectral region atits absorbance maximum, but possesses comparatively little absorbancearound 20 nm below its absorbance maximum.

We have now discovered that certain dyes set forth below form stableliquid-crystalline phases when dispersed in wet aqueous media(preferably containing a hydrophilic colloid such as gelatin) andprovide the advantages set for in the above objects of the invention.The said liquid-crystalline dye dispersion can be formed by dispersingpowdered dye or a milled dye slurry into an aqueous medium, preferablycontaining gelatin or other hydrophilic colloid, over a specifiedconcentration and temperature range, using the methods set forth herein.

One aspect of this invention comprises a solvent, preferably an aqueousmedium, having dispersed therein a liquid-crystal forming dye ofstructural Formula I:

[D-(X)_(m)]-(Y)_(n)

wherein

D is a light-absorbing chromophore other than a cyanine dye or abarbituric acid oxonol dye.

Each Y contains an ionic or a nonionic solubilizing substituent or agroup with a pKa value of less than 4 in water.

Each X is a nonionic substituent.

n is 0 to 10; preferably 1 to 6, more preferably 1 to 3.

m is 0 to 10, preferably 1 to 6, more preferably 1 to 3, and

the resulting dye forms a liquid-crystalline phase in a solvent, such asan aqueous media, including hydrophilic colloids, when dispersed asdescribed herein. Protocol for determining the presence of dyeliquid-crystalline phases is also described herein.

Another preferred embodiment of the invention comprises an imagingelement containing a liquid crystal-forming dye of structural Formula I.

Still another preferred embodiment of the invention comprises aradiation-sensitive element, such as a photographic element, containinga liquid-crystal forming dye of structural Formula I.

Yet another preferred embodiment of the invention comprises a method ofpreparing a liquid-crystalline dye dispersion which comprises adding adye of structural Formula I to an aqueous medium at a temperature offrom about 2° C. to about 100° C. and agitating the mixture for about 5minutes to about 48 hours.

Advantageous Effects of the Invention

This invention provides a dye, useful as a filter dye or light-absorbingcompound in an imaging element, and especially in a radiation-sensitiveelement, such as a photographic element, which when dispersed in anaqueous medium, for example aqueous gelatin, dissolves thenspontaneously forms a lyotropic liquid-crystalline phase whichconstitutes an unusually well-ordered and thermodynamically stable dyestate. A dye in the liquid-crystalline state often possesses a coatedλ_(max) which is substantially bathochromic or hypsochromic to that ofits monomeric isotropic solution (non-liquid crystalline) state andexhibits exceptionally high covering power at its coating λ_(max).Further, the liquid-crystalline dye phase often exhibits sharp-cuttingbathochromic and/or hypsochromic spectral features absorbing strongly atits coating λ_(max), while absorbing comparatively little light atwavelengths just below or just above its absorbance maximum. Further,the liquid-crystalline dye phase often possesses an unusually narrowhalfbandwidth. The dyes of this invention can be formulated forincorporation into a photographic element using, for example,conventional ball-mill or media-mill procedures for producing dyedispersions (SPD's), or more simply as direct gelatin dispersions(DGD's) for incorporation in a photographic element, as discussed morefully below. In the photographic element, dyes in thespontaneously-formed liquid-crystalline state exhibit little, if anytendency to wander, and upon processing many are substantially free ofpost-process stain problems.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, the dispersion of this invention comprises aliquid-crystal forming dye of Formula I:

[D-(X)_(m)]-(Y)_(n)

wherein

D is a light-absorbing chromophore other than a cyanine dye or abarbituric acid oxonol dye.

Each Y contains an ionic or a nonionic solubilizing substituent or agroup with a pKa value of less than 4 in water.

Each X is a nonionic substituent.

n is 0 to 10; preferably 1 to 6, more preferably 1 to 3.

m is 0-10, preferably 1 to 6, more preferably 1 to 3, and

the resulting dye forms a liquid-crystalline phase in solvent such as anaqueous media, including hydrophilic colloids, when dispersed asdescribed herein. Protocol for determining the presence of dyeliquid-crystalline phases is also described herein.

In Formula I, D represents a dye residue. Examples of dye classes fromwhich D is derived include but are not restricted to an arylidene dye,an oxonol dye, a merocyanine dye, a styryl dye, a coumarin dye, an azodye, an azomethine dye, a hemioxonol dye, a metal-chelated dye, atriarylmethane dye, an indoaniline dye, a chalcone dye, an anthraquinonedye, a butadiene dye, with the exception of a barbituric acid oxonol dyeand a cyanine dye. In non-imaging embodiments of the invention, D ispreferably other than azo dye. Useful dye include those absorbing in theUV region (below 400 nm), the visible region (400-700 nm), and theinfrared region (above 700 nm).

Each Y may independently be a group containing an ionic or nonionicsolubilizing substituent, and each X may independently be a nonionicsubstituent, each X and Y being present in number and combination suchthat the resulting dye forms a liquid-crystalline phase when dispersedor dissolved in a solvent. For water-based solvent media, examples ofsolubilizing groups contained in Y include, but are not restricted tocarboxylate (CO₂ ⁻), sulfo (SO₃ ⁻), sulfato (OSO₃ ⁻), sulfate (SO₄ ⁻),phosphate, phosphonate, trialkylammonium (R₃N⁺), pyridinium,alkylpyridinium , hydroxylate (O⁻), enolate (C═C—O⁻), dicyanovinylate(C═CCH(CN)₂ ⁻), alkyl ethers such as (CH₂OCH₂CH₃), zwitterionic groupssuch as amino acids, phosphatidyl choline, phosphatidyl ethanolamine,and phosphatidyl serine, and groups with a pKa value below 4 andpreferably below 3.8 such as sulfonic acid, acylsulfonamide (CONHSO₂R),saccarin moeities (cyclic acylsulfamdes), and sulfonylsulfonamido(SO₂NHSO₂R). Y or the solubilizing substituent contained in Y may beattached to the dye in any way; it may be attached directly to thechromophoric moeity itself, D, or to X or may be attached to the dye aspart of a linking group such as a substituted or unsubstituted alkyl oraryl group. In the case where n is 0, the solubilizing substituent maybe incorporated as part of the actual chromophoric moiety D (e.g., theenolate portion of an oxonol dye. Examples of groups for X include, butare not restricted to aryl, alkyl, aralkyl, halogen, cycloalkyl, alkoxy,alkylamino, acyl, carboxy, carboxyalkyl, sulfonamido or alkylthio, andmore preferably are phenyl, halogen, and benzo (fused phenyl).

In another preferred embodiment of the invention the liquid-crystalforming dye of structural Formula I is an oxonol dye of Formula II:

wherein A¹ and A² are ketomethylene or activated methylene moieties,L¹-L⁷ are substituted or unsubstituted methine groups, (including thepossibility of any of them being members of a five or six-membered ringwhere at least one and preferably more than one of p, q, or r is 1); M⁺is a cation, and p, q and r are independently 0 or 1.

In another preferred embodiment of the invention the liquid-crystalforming dye of structural Formula 11 is an oxonol dye of Formulae II-Athrough II-B:

Wherein W¹ and Y¹ are the atormis required to form a cyclic activatedmethylene/ketomethylene moiety; R¹ and R³ are aromatic or heteroaromaticgroups; R² and R⁴ are electron-wvithdrawing groups; G¹ to G⁴ is O ordicyanovinyl (—C(CN)₂)) and p, q, and r are defined as above, and L¹ toL⁷ are defined as above.

In an even more preferred embodiment of the invention, theliquid-crystal forming dye of Formula II is an oxonol dye of FormulaIII:

wherein Q¹ and Q² represent the non-metallic atoms required to form asubstituted or unsubstituted 5 or 6-membered heterocyclic or carbocyclicring, preferably a substituted or unsubstituted aromatic orheteroaromatic ring including any fused polycyclic moeity; or a dye ofFormula III-A:

wherein R⁵ to R⁸ each individually represent amino, alkylamino,dialkylamino, hydroxy, alkylthio, halogen, cyano, alkylsulfone,arylsulfone, or substituted or unsubstituted alky, aryl, heteroaryl, oraralkyl, and L¹ to L⁷, M⁺, and p, q and r are defined as described abovefor Formula III.

In another preferred embodiment of the invention, the liquid-crystalforming dye of Formula II is an oxonol dye of Formula III-B:

wherein R⁹ to R¹⁶ each independently represents hydrogen, substituted orunsubstituted alkyl, or cycloalkyl; alkenyl, substituted orunsubstituted aryl, heteroaryl or aralkyl; alkylthio, hydroxy,hydroxylate, alkoxy, amino, alkylamino, halogen, cyano, nitro, carboxy,acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl, or groupscontaining solubilizing substituents as described above for Y. Anyadjacent pair of substituents among R⁹ through R¹⁶ may together form afused carbocyclic or heterocyclic aromatic or aliphatic ring. L¹ throughL⁷ are methine groups as described above, M⁺ is a cation, and p, q and rare independently 0, or 1 as described above.

In a preferred embodiment, the substituents R⁹ to R¹⁶ do not contain thegroups described by Y.

In yet another preferred embodiment of the invention the liquid-crystalforming dye of structural Formula I is a merocyanine of Formula IV:

wherein A³ is a ketomethylene or activated methylene moiety as describedabove; each L⁸ to L¹⁵ are substituted or unsubstituted methine groups(including the possibility of any of them being members of a five orsix-membered ring where at least one and preferably more than 1 of s, t,v or w is 1); Z¹ represents the non-metallic atoms necessary to completea substituted or unsubstituted ring system containing at least one 5 or6-membered heterocyclic nucleus; R¹⁷ represents a substituted orunsubstituted alky, aryl, or aralkyl group; with the proviso that atleast one substituent on the dye of Formula IV contains a ionic ornon-ionic solubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I.

In yet another preferred embodiment of the invention the liquid-crystalforming dye of structural Formula I is a merocyanine of Formula IV-A:

wherein A⁴ is an activated methylene moeity or a ketomethylene moeity asdescribed above, R¹⁸ is substituted or unsubstituted aryl, alkyl oraralkyl, R¹⁹ to R²² each individually represent hydrogen, alkyl,cycloalkyl, alkeneyl, substituted or unsubstituted aryl, heteroaryl oraralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino,halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing solubilizingsubstituents as described above for Y. L⁸ through L¹³ are methine groupsas described above for L¹ through L⁷, Y² is O, S, Te, Se, NR_(x), orCR_(y)R_(z) (where Rx, Ry and Rz are alkyl groups with 1-5 carbons), ands and t and v are independently 0 or 1; with the proviso that at leastone substituent on the dye of Formula IV-A contains an ionic ornon-ionic sclubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I.

In a preferred embodiment, Y² is O, S, NR, or CR_(y)R_(z), and the sumof s, t and v is 1 or 2.

In another especially preferred embodiment the liquid-crystal formingdye of Formula IV is a merocyanine dye of Formula V-A:

wherein R²³ is a substituted or unsubstituted aryl, heteroaryl, or asubstituted or unsubstituted amino group; G⁵ is O or dicyanovinyl(C(CN)₂),E¹ is an electron-withdrawing group, R¹⁸ to R²², L⁸ to L¹³, Y²,and s, t and v are as described above; with the proviso that at leastone substituent on the dye of Formula V-A is a ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water asdescribed for Y in Fonnula I.

In a preferred embodiment, Y² is O or S, E¹ is cyano, R²³ is asubstituted or unsubstituted phenyl or heteroaromatic ring, R¹⁸ issulfoalkyl and sum of s, t and v is 1 or 2. In an especially preferredembodiment, G⁵ is dicyanovinyl, E¹ is cyano, and Y² is O.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula IV is a dye of Formula V-B:

wherein G⁶ is oxygen (O) or dicyanovinyl (C(CN)₂),R⁹ to R¹² groups eachindividually represent groups as described above, and R¹⁸, R¹⁹ throughR²², Y², L⁸ through L¹³, and s, t and v are as described above, with theproviso that at least one substituent on the dye of Formula V-B is aionic or non-ionic solubilizing group or a group with a pKa value lessthan 4 in water as described for Y in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula V-C:

wherein R²⁵ groups each individually represent the groups described forR¹⁹ through R²² above, Y³ represents O, S, NR_(x), or CR_(y)R_(z) (whereRx, Ry and Rz are alkyl groups with 1-5 carbons), x is 0, 1, 2, 3 or 4,R²⁴ represents aryl, alkyl or acyl, and Y² , R¹⁸, R¹⁹ through R²², L⁸through L¹³, and, s, t and v are as described above; with the provisothat at least one substituent on the dye of Formula V-C is a ionic ornon-ionic solubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I.

In a preferred embodiment Y² and Y³ are O or S, R¹⁸ is sulfoalkyl, andthe sum of s,t and v is 1 or 2.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula V-D:

wherein E² represents an electron-withdrawing group, preferably cyano,R²⁶ represents aryl, alkyl or acyl, and Y², R¹⁸, R¹⁹ through R²², L⁸through L¹³, and, s, t and v are as described above; with the provisothat at least one substituent on the dye of Formula V-D contains anionic or non-ionic solubilizing group or a group with a pKa value lessthan 4 in water as described for Y in Formula I. In a preferredembodiment, E² is cyano and R¹⁸ is sulfoalkyl.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula V-E:

wherein R²⁷ is a hydrogen, substituted or unsubstituted alkyl, aryl oraralkyl, R²⁸ is substituted or unsubstituted alkyl, aryl or aralkyl,alkoxy, amino, acyl, alkoxycarbonyl, carboxy, carboxylate, cyano, ornitro; R¹⁸ to R²², L⁸ to L¹³, Y², and s, t and v are as described above;with the proviso that at least one substituent on the dye of Formula V-Econtains an ionic or non-ionic solubilizing group or a group with a pKavalue less than 4 in water as described for Y in Formula I. In apreferred embodiment, R²⁷ is an aryl group, and the sum of s, t and v is1 or 2.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula V-F:

wherein R²⁹ and R³⁰ are each independently a hydrogen, substituted orunsubstituted alkyl, aryl or aralkyl, Y⁴ is O or S, R¹⁸ to R²², L⁸ toL¹³, Y², and s, t and v are as described above; with the proviso that atleast one substituent on the dye of Formula V-F contains an ionic ornon-ionic solubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I. In a preferred embodiment the sumof s, t and v is 1 or 2.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula VI:

wherein A⁵ is a ketomethylene or activated methylene, L¹⁶ through L¹⁸are substituted or unsubstituted methine, R³¹ is alkyl, aryl or aralkyl,Q³ represents the non-metallic atoms necessary to complete a substitutedor unsubstituted ring system containing at least one 5- or 6-memberedheterocyclic nucleus, R³² represents groups as described above for R¹⁹to R²², y is 0, 1, 2, 3 or 4, z is 0, 1 or 2; with the proviso that atleast one substituent on the dye of Formula VI contains an ionic ornon-ionic solubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula VI is a dye of Formula VII:

wherein A⁶ is a ketomethylene or activated methylene, L¹⁶ through L¹⁸are methine groups as described above for L1 through L⁷, R³³ issubstituted or unsubstituted alkyl, aryl or aralkyl, R³⁴ is substitutedor unsubstituted aryl, alkyl or aralkyl, R³⁵ groups each independentlyrepresent groups as described for R¹⁹ through R²², z is 0, 1 or 2, and ais 0, 1, 2, 3 or 4; with the proviso that at least one substituent onthe dye of Formula VII contains an ionic or non-ionic solubilizing groupor a group with a pKa value less than 4 in water as described for Y inFormula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula VIII:

wherein A⁷ represents a ketomelthylene or activated methylene moiety,L¹⁹ through L²¹ represent methine groups as described above for L¹through L⁷, R³⁶ groups each individually represent the groups asdescribed above for R¹⁹ through R²², b represents 0 or 1, and crepresents 0, 1, 2, 3 or 4; with the proviso that at least onesubstituent on the dye of Formula VIII is a ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water asdescribed for Y in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula IX:

wherein A⁸ is a ketomethylene or activated methylene, L¹⁹ through L²¹and b are as described above, R³⁹ groups each individually represent thegroups as described above for R¹⁹ through R²², and R³⁷ and R³⁸ eachindividually represent the groups as described for R¹⁸ above, and drepresents 0, 1, 2, 3 or 4; with the proviso that at least onesubstituent on the dye of Formula IX is a ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water asdescribed for Y in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula X:

wherein A⁹ is a ketomethylene or activated methylene moiety, L²² throughL²⁴ are methine groups as described above for L¹ through L⁷, e is 0 or1, R⁴⁰ groups each individually represent the groups described above forR¹⁹ through R²², and f is 0, 1, 2, 3 or 4; with the proviso that atleast one substituent on the dye of Formula X contains an ionic ornon-ionic solubilizing group or a group with a pKa value less than 4 inwater as described for Y in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula XI:

wherein A¹⁰ is a ketomethylene or activated methylene moiety, L²⁵through L²⁷ are methine groups as described above for L¹ through L⁷, gis 0, 1 or 2, and R³⁷ and R³⁸ each individually represent the groupsdescribed above for R18; with the proviso that at least one substituenton the dye of Formula XI contains an ionic or non-ionic solubilizinggroup or a group with a pKa value less than 4 in water as described forY in Formula I.

In an another preferred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula XII:

wherein A¹¹ is a ketomethylerie or activated methylene moiety, R⁴¹groups each individually represent the groups described above for R¹⁹through R²², R³⁷ and R³⁸ each represent the groups described for R18,and h is 0, 1, 2, 3, or 4; with the proviso that at least onesubstituent on the dye of Formula XII contains an ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water asdescribed for Y in Formula I.

In an another p:referred embodiment of the invention, the liquid-crystalforming dye of Formula I is a dye of Formula XIII:

Q⁴—N═N—Q⁵  Formula XIII

wherein Q⁴ and Q⁵ each represents the atoms necessary to form at leastone heterocyclic or carbocyclic, fused or unfused 5 or 6-membered-ringconjugated with the azo linkage; with the proviso that at least onesubstituent on the dye of Formula XIII contains an ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water asdescribed for Y in Formula I.

Still another preferred embodiment of the invention comprises an imagingelement containing at least one liquid crystal-forming dye of structuralFormulae I-XIII.

Still another preferred embodiment of the invention comprises aradiation-sensitive element, such as a photographic element, containinga liquid-crystal forming dye of structural Formulae I-XIII.

In Formulae II, IV, and VI-XII, activated methylene or ketometylenemoieties represented by A¹ through A¹¹ are well known in the art and aredescribed, for example, in Hamer, The Cyanine Dyes and RelatedCompounds, pages 469-494 and 595-604. In accordance with the presentinvention, preferred active methylene groups include, but are notrestricted to those derived from benzoylacetonitrile, 2-pyrazolin-5-one,pyrazolidindione, tricyanopropene, barbituric acid, indanedione,dicyanovinylindanedione, bis(dicyanovinyl)indanedione, pyrrolinone,furanone (such as cyanophenylfuranone and derivatives) benzothiophenedioxide, dicyanovinylbenzothiophene dioxide, rhodanine, benzofuranone,chromandione, cyclohexanedione, isoxazolinone, pyrazolopyridine,pyridone and pyrandione, and any of these moieties may be optionallysubstituted with ionic or non-ionic solubilizing group(s) or anionizable group with a pKa value less than 4 in water.

In Formulae II and III, M⁺ is a cation such as H⁺, Et₃NH⁺, C₅H₅NH⁺, Na⁺,and K⁺. “Group” wherever used in the present application includes thepossibility of being substituted or unsubstituted, R², R⁴, E¹ and E² areelectron-withdrawing substituents which are discussed in March, AdvancedOrganic Chemistry, pages 20-21, 228-229, 386-387 and 494-497. Groups forR², R⁴, E¹ and E² may include cyano, acyl, benzoyl, phenacyl,aminocarbonyl, alkoxycarbonyl, aryl, nitro or arylsulfonyl oralkylsulfonyl.

The solubilizing group contained in Y may be chosen easily by oneskilled in the art. Examples of ionic solubilizing groups includeanionic groups such as carboxylate (CO₂ ⁻), sulfo (SO₃ ⁻), sulfato (OSO₃⁻), sulfonate (SO₄ ⁻), hydroxylate (O⁻), enolate (C═C—O⁻),dicyanovinylate (C═C—C(CN)₂ ⁻), phosphate, and phosphonate, cationicgroups such as ammonium, alkylammonium, dialkylammonium,trialkylammonium (alkyls may be substituted), and pyridinium, andzwitterionic groups such as amino acids, phosphatidyl choline,phosphatidyl ethanolamine, and phosphatidyl serine. Examples ofnon-ionic solubilizing groups contained in Y include alkyl ethers suchas (—O(CH₂)_(n)OCH₃ or (CH₂OCH₂OCH₃). Y may also contain an ionizablegroup with a pKa in water less than 4. Examples of ionizable groups withpKa values below 4 in water include sulfonic acid (SO₃H), acylsulfomido(CONHSO₂R), saccarhin (cyclic acylsulfonamide), sulfonylsulfonamido(SO₂NHSO₂R), dinitroalkyl, dinitrophenol, and activated carboxy moietiessuch as dichloroalkylcarboxy, and salicylic acid. In all structuraldescriptions, Y may be either an ionic or nonionic solubilizing group orgroup with a pKa value below 4, or Y may be a group containing one ofthese said solubilzing moeities.

The substituent pairs of R³⁷ and R³⁸, may together represent thenon-metallic atoms required to form a 5- or 6-membered ring. Q¹ and Q²may represent the non-metallic atoms required to form at least one 5- or6-membered aromatic ring. Examples of these fused rings includepyridine, benzene, furan, pyrrole and indole. The groups formed by Q⁴and Q⁵ include 5 or 6-membered, fused or unfused, aromatic orheteroaromatic rings including pyridine, pyrazole, pyrrole, furan,indole, thiophene or fused ring systems such as benzindole andbenzoxazole.

The atoms represented by Z¹ can complete a 5- or 6-membered heterocyclicnucleus which can be fused with additional substituted or unsubstitutedrings such as a benzo ring. Suitable heterocyclic nuclei are of the typecommonly used in senstizing dyes and are well known in the art. Many,for example, are described in Mees and James, Theory of The PhotographicProcess, 4^(th) edition, pages 195-203. Useful heterocyclic nucleiinclude thiazole, selenazole, oxazole, telerozole, imidazole. indole,benzoxazole, benzothiazole, benzimidazole or benzindole. In a preferredembodiment, Z¹ represents the atoms necessary to complete a substitutedor unsubstituted benzoxazole, benzothiazole, benzimidazole or benzindolenucleus.

Any L group may be substituted or unsubstituted. This includes thepossibility that any of them may be members of a 5 or 6-membered ring.

In Formulae IV and V preferred substituents for R¹⁹-R²² include groupssuch as phenyl, benzo (fused phenyl), halogen (especially chloro,fluoro, bromo), and pyrrole.

Methine groups may be substituted with, for example, an alkyl, alkenyl,aryl, aralkyl, cycloalkyl, or heterocyclic group or, as mentioned above,if more than one of p, q, or r is 1, two or more methine groups togetherwith their substituents may form a 5- or 6-membered carbocyclic orheterocycllic ring.

In general, when reference in this application is made to a particularmoiety or group it is to be understood that such reference encompassesthat moiety whether unsubstituted or substituted with one or moresubstituents (up to the maximum possible number). For example, “alkyl”or “alkyl group” refers to a substituted or unsubstituted alkyl, while“benzene group” refers to a substituted or unsubstituted benzene (withup to six substituents). Generally, unless otherwise specificallystated, substituent groups usable on molecules herein include anygroups, whether substituted or unsubstituted, which do not destroyproperties necessary for the photographic utility. Examples ofsubstituents on any of the mentioned groups can include knownsubstituents, such as: halogen, for example, chloro, fluoro, bromo,iodo; hydroxy; alkoxy, particularly those “lower alkyl” (that is, with 1to 6 carbon atoms, for example, methoxy, ethoxy; substituted orunsubstituted alkyl, particularly lower alkyl (for example, methyl,trifluoromethyl); thioalkyl (for example, methylthio or ethylthio),particularly either of those with 1 to 6 carbon atoms; substituted orunsubstituted alkenyl, preferably of 2 to 10 carbon atoms (for example,ethenyl, propenyl, or butenyl); substituted and unsubstituted aryl,particularly those having from 6 to 20 carbon atoms (for example,phenyl); and substituted or unsubstituted heteroaryl, particularly thosehaving a 5 or 6-membered ring containing 1 to 3 heteroatoms selectedfrom N, O, or S (for example, pyridyl, thienyl, furyl, pyrrolyl); acidor acid salt groups such as any of those described below; hydroxylate,amino, alkylamino, cyano, nitro, carboxy, carboxylate, acyl,alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl, sulfo, sulfonate,alkylammonium, and an ionizable group with a pKa value below 4 inwater;and others known in the art. Alkyl substituents may specificallyinclude “lower alkyl” (that is, having 1-6 carbon atoms), for example,methyl, ethyl, and the like. Further, with regard to any alkyl group oralkylene group, it will be understood that these can be branched orunbranched and include ring structures.

Examples of preferred dyes of the invention are listed below.

TABLE 1

Dye R² R³ R⁴ R⁵ M⁺ 1-1 H H Cl H H 1-1A H H Cl H TEAH 1-2 H H F H H 1-2AH H F H TEAH 1-3 H OMe H H H 1-4 Cl H H Cl TEAH 1-5 H Me H H TEAH 1-6 MeH H H H 1-7 H H Ph H TEAH 1-7A H H Ph H Na 1-8 H Cl H H H 1-9 H Ac H H H1-10 H Ac Cl H Pyr 1-11 H OH H H H 1-12 H H OH H TEAH 1-13 H H Br H Pyr1-14 H OMe Cl H TEAH 1-15 H H H F H 1-16 H NHAc H H H 1-17 H Cl Me HTEAH 1-17A H Cl Me H H 1-18 H H COONa H Na 1-19 H Me H H Pyr 1-20 H OHOH H H

TABLE 2

R¹ R² R³ R⁴ R⁵ M⁺ 2-1 H H H Cl H H 2-1A H H H Cl H TEAH 2-2 H Me H F HTEAH 2-3 H H OMe H H H 2-4 H H Me H H H 2-5 H H H H Cl H 2-6 H H OMe OMeH H 2-7 H H H Ph H Na 2-8 H H Cl H H H 2-9 H H Ac H H H 2-10 H H H COONaH Na 2-11 Me H H Cl H TEAH 2-11A Me H H Cl H H 2-12 H H Me H H TEAH 2-13Me H Me H H TEAH 2-14 H H OH H H H 2-15 H H H OH H TEAH

TABLE 3

Dye R¹ R² R³ R⁴ R⁵ M⁺ 3-1 Me H OMe OMe H H 3-1A Me H OMe OMe H TEAH 3-2H H H Cl H H 3-3 H H OH H H TEAH 3-4 Me H OH H H TEAH 3-5 Et H H OMe H H3-6 Me H H Ph H Na 3-7 Me H H F H TEAH

TABLE 4

TABLE 5

Dye R¹ R² R³ R⁴ R⁵ R⁶ M⁺/X⁻ Y 5-1 Ph sp⁻ H H H H Na⁺ O 5-2 Ph sp⁻ H Cl HH Na⁺ O 5-3 Ph sp⁻ H Ph H H Na⁺ O 5-4 (p-NHSO2Me)—Ph sp⁻ H Cl H H Na⁺ O5-5 Ph sp⁻ H

H H Et₃NH⁺ O 5-6 (p-CO₂M)—Ph sp⁻ H Ph H H Na O 5-7 Ph sp⁻ R³-R⁴ = benzoH H Na⁺ O 5-8

sp⁻ H H H H Na⁺ O 5-9 Ph sp⁻ H R⁴-R⁵ = benzo H Na⁺ O 5-10 p-NHSO2Me)—Phsp⁻ H

H H Et₃NH⁺ O 5-11 Ph

H H H H Na⁺ O 5-12 Ph Me H SO₃ ⁻ H H Pyr⁺ O 5-13 (p-Cl)—Ph sp⁻ H Cl H HNa⁺ S 5-14 (p-Cl)—Ph sp⁻ H Ph H H Et₃NH⁺ O 5-15 Ph sp⁻ H Cl H H Et₃NH⁺ S5-16 (p-CO₂M)—Ph sp⁻ R³-R⁴ = benzo H H Na⁺ S 5-17 Ph sp⁻ H Ph H H Na⁺ S5-18 Ph sp⁻ H Me H H Na⁺ O 5-19 (p-Cl)—Ph sp⁻ H Cl H H Pyr⁺ O 5-20(m-OMe)—Ph sp⁻ H Ph H H Et₃NH⁺ O 5-21 Ph tmap⁺ H Ph H H Br⁻ O 5-22 Phtmap⁺ H Cl H H Br⁻ O 5-23 Ph tmap⁺ H Ph H H Br⁻ O 5-24 Ph 3-sb⁻ H Ph H HEt₃NH⁺ O 5-25 (p-NHAc)—Ph sp⁻ R³-R⁴ = benzo H H Et₃NH⁺ S 5-26 Ph tmap⁺ HCl H H pTs⁻ S 5-27 Ph 3-sb⁻ H R⁴-R⁵ = benzo H Et₃NH⁺ S

TABLE 6

Dye R¹ R² R³ R⁴ R⁵ R⁶ M⁺/X⁻ Y 6-1 Ph sp⁻ H Ph H H Et₃NH⁺ O 6-2 Ph sp⁻ HH H H Et₃NH⁺ O 6-3 Ph sp⁻ H R⁴-R⁵ = benzo H Et₃NH⁺ O 6-4 (p-NHSO2Me)—Phsp⁻ R³-R⁴ = benzo H H Na⁺ O 6-5

sp⁻ H H H H Et₃NH⁺ O 6-6 Ph sp⁻ H Ph H H Na S 6-7 Ph sp⁻ H Cl H H Et₃NH⁺S 6-8 (p-CO₂M)—Ph sp⁻ H R⁴-R⁵ = benzo H Na⁺ S 6-9 (p-Cl)—Ph sp⁻ H Ph H HNa⁺ O 6-10 (p-NHSO2Me)—Ph sp⁻ H Cl H H Et₃NH⁺ S 6-11 Ph Et H SO₃ ⁻ H HNa⁺ O 6-12 Ph sp⁻ H Cl H H Et₃NH⁺ O 6-13 Ph sp⁻ R³-R⁴ = benzo H H Et₃NH⁺O 6-14 Ph

H H H H Et₃NH⁺ O 6-15 Ph

H Cl H H Et₃NH⁺ O 6-16 (p-Cl)—Ph sp⁻ H

H H Pyr⁺ O 6-17

sp⁻ H Cl H H Na⁺ O 6-18 Ph tmap⁺ H H H H Br⁻ O 6-19 Ph tmap⁺ H Cl H HBr⁻ O 6-20 Ph tmap⁺ H Ph H H Br⁻ O 6-21 (p-CO2M)—Ph sb⁻ H Ph H H Na⁺ O6-22 Ph tmap⁺ R³-R⁴ = benzo H H Br⁻ O 6-23 Ph tmap⁺ H R⁴-R⁵ = benzo HBr⁻ S

TABLE 7

TABLE 8

Dye R¹ R² R³ R⁴ R⁵ R⁶ M⁺/X⁻ Y n 8-1 NH₂ sp⁻ H Ph H H Na⁺ O 0 8-2 NAc₂sp⁻ H R⁴-R⁵ = benzo H Et₃NH⁺ S 0 8-3 NAc₂ sp⁻ R³-R⁴ = benzo H H K⁺ S 08-4 NAc₂ sp⁻ H H H H Et₃NH⁺ S 1 8-5

sp⁻ H Ph H H Et₃NH⁺ O 1 8-6 NAc₂ sp⁻ H Ph H H Na O 1 8-7 NAc₂ sp⁻ H HR⁵-R⁶ = benzo Na⁺ S 1 8-8 NHPh sp⁻ H R⁴-R⁵ = benzo H Na⁺ S 1 8-9(p-Cl)—NHPh sp⁻ H Ph H H Na⁺ O 0 8-10 NH₂ sp⁻ H H H H Et₃NH⁺ S 1

TABLE 9

TABLE 10

Dye R¹ R² R³ R⁴ R⁵ R⁶ M⁺/X⁻ Y n 10-1 Ph sp⁻ H H H H Na⁺ O 0 10-2 Ph sp⁻H R⁴-R⁵ = benzo H Et₃NH⁺ O 0 10-3 Ph sp⁻ R³-R⁴ = benzo H H K⁺ O 0 10-4Ph sp⁻ H Cl H H Et₃NH⁺ S O 10-5 Ph cb⁻ H H H H Na⁺ O 0 10-6 Ph sp⁻ H

H H Et₃NH⁺ O 0 10-7

sp⁻ R³-R⁴ = benzo H H K⁺ S 1 10-8 Ph sp⁻ H Ph H H Et₃NH⁺ O 1

TABLE 11

TABLE 12

TABLE 13

TABLE 14

TABLE 15

The dyes of Formulae I-XIII can be prepared by synthetic techniqueswell-known in the art, as illustrated by the synthetic examples below.Such techniques are further illustrated, for example, in “The CyanineDyes and Related Compounds”, Frances Hamer, Interscience Publishers,1964.

The liquid-crystalline dye dispersions of this invention may be preparedby well-known methods commonly employed for preparing solid particle dyedispersions. Here, a slurry of the dye in an aqueous medium comprisingwater and a surfactant or water-soluble polymer is subjected to amilling procedure such as ball-milling, sand-milling, media-milling orcolloid-milling (preferably media-milling). The dye slurry can then bemixed with aqueous gelatin at an appropriate concentration (preferably≦30% w/w) and at a temperature (preferably 20 to 90° C.)for use in aphotographic element.

In another preferred embodiment, the liquid-crystalline dye dispersionsof this invention may be prepared using a direct gelatin dispersion(DGD) method wherein the finely powdered dye or aqueous slurry thereofis simply mixed or agitated with water or with an aqueous mediumcontaining gelatin (or other hydrophilic colloid) at an appropriateconcentration (preferably ≦30% w/w) and at a temperature (preferably 0to 100° C.).

In either of the preferred methods, the dyes may be subjected toelevated temperatures before and/or after gelatin dispersion, but toobtain desirable results, this heat treatment is carried out preferablyafter dispersing in gelatin. The optimal temperature range for preparinggelatin-based dispersions is 20° C.-100° C., depending on theconcentration of the gelatin, but should remain below the decompositionpoints of the dyes, and, preferably for the range of 5 minutes to 48hours. A similar heat treatment may be applied, if so desired, to dyesprepared by milling methods as solid particle dispersions before and/orafter dispersion in aqueous gelatin to obtain effective results.Furthermore, if so desired, pH and/or ionic strength and solventcomposition adjustments, for example, may be utilized to control thesolubility and liquid crystal-forming properties of dyes prepared usingSPD or DGD formulation techniques. The direct gelatin dispersion methodis advantageous in that it does not necessarily require the use oforganic solvents, surfactants, polymer additives, electrolytes, millingprocesses, pH control or the like. It is generally simpler, faster, moreforgiving and more flexible than milling processes. A related methoddescribed by Boettcher for preparing concentrated sensitizing dyedispersions in aqueous gelatin (PCT WO 93/23792) is equally effectivewhen applied to the inventive dyes. The entire disclosure of WO 93/23792is incorporated herein by reference. The inventive lyotropicliquid-crystalline dye dispersions may be incorporated directly intoimaging elements.

Solid particle dispersion and direct gelatin dispersion formulations ofthe compound of Formula (I-XIII) are useful as general purpose filterdyes, alone or in combination with other filter dyes in photographicelements. The dyes formulated as described above possess a pronouncedtendency to form liquid crystal phases spontaneously at a variety ofpH's, including typical coating pH's of 6 or less (generally 4-6) suchthat they do not substantially wander from the layer in which they arecoated. However, they are highly soluble at processing pH's of 8 or more(generally 8-12), such that they are often still fully removed duringphotographic processing.

Our invention comprises a wide variety of dye classes which arefunctionalized to form liquid crystalline phases in solvents, especiallywater, and hydrophilic colloids such as aqueous gelatin. These materialswould be especially useful as filter dyes in photographic systems asdescribed above, as spectral sensitizers, and in non-photographicimaging applications such as inkjet, barcoding, and thermally-developedimaging systems.

There are few teachings addressing dye lyotropic liquid-crystallinephases. Additionally, no teachings are provided that would enable oneskilled in the art to design and synthesize dyes capable of formingliquid crystals or to influence their formation in imaging elements.

For most materials, it is generally accepted that only three states ofmatter exist; namely, solids, liquids and gases. However, some materialsexhibit a fourth state of matter commonly referred to as a liquidcrystal phase (or mesophase). Liquid crystal phases are neithercrystalline solids nor isotropic liquids, but exhibit some of thecharacteristics of both. A liquid crystal phase can be described simplyas being a liquid with a certain degree of molecular order. As describedbelow, this molecular order gives rise to measurable anisotropy in thebulk properties of a material that is otherwise much like a liquid.Consequently, the physical properties of liquid-crystalline materialsare unique and distinct from those of solids and liquids. Thesedifferences can be utilized to advantage in the formulation ofphotographic elements and also allow detection of the liquid crystalphase by a variety of optical and spectroscopic techniques.

Liquid crystals can be classified as thermotropic or lyotropic. The dyecompositions of the current invention are of the lyotropic type,however, for puposes of comparison, we first give a brief descriptionthe thermotropic type: Some crystalline compounds do not yield anisotropic liquid immediately upon melting, instead, the newly formed“melt” is a liquid crystal phase (mesophase). In the simple cases,further heating results in the formation of an ordinary isotropicliquid. The phase that exists above the melting point of the crystallinesolid but below the formation temperature for the isotropic liquid isknown as a thermotropic liquid crystal phase. In some cases, heating theinitially formed mesophase does not result in an isotropic liquid, butrather, to one or more intermediate liquid crystal phases, and finally,the last formed of these, upon further heating, yields the isotropicliquid. All of the mesophases formed in this way are conventionallyclassified as thermotropic. The term thermotropic liquid crystal is alsoextended to include eutectic mixtures of compounds. Thermotropic liquidcrystals are generally colorless organic materials and are typicallyhydrophobic (water-insoluble) in character. They are commonly employedin electro-optical display devices, for example digital watches andcalculators.

In contrast, spontaneous formation of lyotropic liquid crystals can beachieved at a fixed temperature by simple addition of a solvent to asuitable solute (mesogen). The solvent is typically (but notnecessarily) water and lyotropic mesophases are stable over finiteranges of both concentration and temperature. Typical lyotropic mesogensare amphiphilic. The term amphiphilic acknowledges that both hydrophobicgroups (e.g. aliphatic, aromatic, etc.) and hydrophilic groups (e.g. CO₂⁻ M⁺, SO₃ ⁻M⁺, SO₄ ⁻M⁺, O(CH₂CH₂O)_(x) etc.) are present on the samemolecule. Examples include, surfactants, lipids, polymers, dyes, anddrugs. The amphiphilic nature and the specific hydrophilic-hydrophobicbalance (HHB) of these molecules influences their tendency to formlyotropic mesophases.

The structural type(s) and stability with respect to concentration andtemperature of the liquid crystalline phase(s) formed are highlymesogen-dependent. For example, Koll et al. (U.S. Pat. No. 4,309,183,Jan. 5, 1982) teach how a lyotropic liquid-crystalline phase of aparticular anionic azo reactive dyestuff can be prepared in water atroom temperature and dye concentrations of 12-35%, for the specific useof dyeing and printing natural and synthetic substrates. However, noreference to such dyes for use in imaging elements has been reported.

Because of the complex interplay of short-range inter-molecular andlong-range inter-aggregate forces controlling lyotropic mesophaseformation, in general it is difficult to predict the likelihood orstability of liquid crystal formation for any given solute-solventcombination.

It is part of the purpose of this invention to demonstrate that a widevariety of chromophores can and do form lyotropic liquid crystals uponsuitable manipulation of substituents. It is a further purpose of thiswork to provide some examples of substituent combinations that areeffective in transforming some quite ordinary dyes classes, that is tosay, dye classes for which mesophases have never been reported, intophotographically useful lyotropic mesogens.

In the preferred embodiment, the amphiphilic filter dye will form anyliquid-crystalline phase upon dispersing said dye in the hydrophilicsolvent medium, typically, but not limited to, water or aqueous gelatin,at the wet laydown (dye concentration) and temperature of choice(preferably □ 30% w/w dye, more preferably ≦10% w/w dye, even morepreferably ≦5% w/w dye and most preferably ≦0.5% w/w dye, between 0° C.and 100° C.). In the most preferred embodiment, said dye mesophase willpossess a layered smectic structure, and in another preferred embodimentthe dye mesophase will possess a nematic or hexagonal structure. We havediscovered that the liquid-crystalline phase stability of lyotropicamphiphilic (particularly ionic) filter dyes may also be sensitive tothe presence of addenda such as gelatin of different types, polymers,organic solvents (such as alcohols, acetone etc.) and surfactants. Forexample, low-levels of common electrolytes can stabilize ionic dyemesophase formation. Enhanced mesophase stability of ionic filter dyes(with respect to both temperature and concentration) may be realizedsimply by the judicious choice of photographic gelatin (e.g. so-calledregular, deionized or decalcified gelatin grades) which containdifferent levels and types of electrolyte cations and anions (e.g.calcium, magnesium, sodium, chloride, sulphate etc.) as a by-product ofgelatin manufacture. Similarly, the use of non-deionized water or theaddition of low salt levels to purified (deionized or distilled) water,can afford enhanced mesophase stability for certain ionic filter dyes.The preferred dyes of this invention are chosen to exhibit stablelyotropic mesophases under the practical conditions generally employedfor their formulation, dispersion, coating and drying. It is understoodthat someone skilled in the art of dyes could, with the guidanceprovided in this disclosure, systematically optimize dye structureand/or solvent conditions to enhance and control dye mesophase formationand stability for a suitable mesogen-solvent combination.

Since mesophase formation is both concentration and temperaturedependent, it is understood that some of the preferred amphiphilicfilter dyes may initially form an isotropic solution phase which willundergo a transition to a more concentrated and thermally-stablemesophase during the drying process (thermal stability of dye mesophasesinvariably increases with dye mesophase concentration).

Some of the preferred amphiphilic filter dyes initially dispersed in thewet hydrophilic colloid medium (e.g. aqueous gelatin) as a diluteliquid-crystalline dye phase, may remain wholly liquid-crystalline upondrying or undergo a (for example, concentration-dependent or ionicstrength-dependent) reversible transition from the liquid-crystallinestate to a crystalline, semi-crystalline. or amorphous solid dye state,or a mixture thereof, during the drying process. However, we have foundthat in such instances the preferred dyes still largely retain theuseful spectral and physical properties associated with the originallydispersed dilute dye mesophase (e.g. absorption envelope providing goodcovering power, layer specificity, incubation stability, rapidprocessing elution and or bleachability). The final physical form of thegelatin-dispersed dye (liquid-crystalline, crystalline, amorphous solid)will depend on the precise phase behaviour of said. dye in relation tothe retained moisture (water) content of the evaporated (dried-down)gelatin film under given conditions of temperature and humidity and thepresence of other solutes. However, according to the invention, dyeswhich remain liquid crystalline when formulated and dispersed in thephotographic vehicle, or those which pass through a transitoryliquid-crystalline phase at any stage during the subsequent coating anddrying process, will afford the useful and unique combination of bothspectral and physical properties, described herein. It should beemphasized that reference in this disclosure to “evaporated” or “dried”coatings refers to coatings of wet aqueous gelatin melts from whichexcess water or solvent has been allowed to evaporate or has beenremoved by drying processes, but which still retain an equilibriummoisture level typical of finished imaging elements especiallyphotographic imaging elements.

According to the invention, the preferred dye chromophores must possesssome added degree of hydrophilicity, imparted by ionic, zwitterionic ornonionic solubilizing groups, to be capable of forming lyotropicliquid-crystalline phases in aqueous-based media. Similarly, if sodesired, for non-aqueous (e.g. organic) solvent applications, the dyeshould possess additional hydrophobic, rather than hydrophilic,solubilizing moieties, such as branched aliphatic chains.

Common mesophase structural types, such as layered smectic (e.g.lamellar), columnar hexagonal and nematic, which possess varying degreesof orientational & translational molecular order, may be formed by manydiverse and disparate lyotropic mesogens. Because of the inherentordered nature of these anisotropic, thermodynamically stable, supramolecular structures, experimental techniques including, for example,small-angle X-ray (or neutron) scattering, polarized-light opticalmicroscopy and quadrupole (e.g. ²³Na, ²H, ¹⁷O, ¹⁴N etc.) NMRspectroscopy may be routinely applied to identifying and characterizingthe structure and physico-chemical properties of lyotropic mesophases.

According to the invention, the preferred dyes can be readily identifiedusing the technique of polarized-light optical microscopy (as describedby N. H. Hartshorne in, “The Microscopy of Liquid Crystals”, MicroscopePublications Ltd., London, England, 1974). In order to ascertain theexact quantitative mesophase behaviour of a given dye-solventcombination, a range of sample mixtures of known composition areprepared (typically dyes dissolved in aqueous gelatin) and viewed inpolarized light as wet thin films (contained within sealed glasscapillary cells of known path length) and slowly-evaporated thin films(hand-coated onto glass microscope slides and air-dried) to establishthe precise concentration and temperature ranges of dye mesophasestability. These same thin-film preparations may also be used toelucidate and quantify the spectral absorption properties of the dyemesophase, such as absorption wavelength, bandwidth, extinctioncoefficient etc. using a uv-vis spectrophotometer.

Simple observations of the characteristic birefringent type-textures andrheology (flow behaviour under shear) displayed by thin-film mesophasepreparations in polarized light are usually sufficient to establish themesophase structural type (e.g. smectic, nematic, hexagonal dependingupon the specific long-range inter-aggregate ordering) as a function ofsolute-solvent concentration and temperature. Dyes forming lyotropicchromonic nematic mesc,phases may be identified from a range of fluid,viscoelastic textures including so-called Schlieren, Tiger-Skin,Reticulated, Homogeneous (Planar), Thread-like, Droplet and Homeotropic(Pseudoisotropic). Lyotropic chromonic hexagonal mesophases usuallydisplay viscous, birefringent Herringbone, Ribbon or Fan-like textureswhile lyotropic chromonic smectic mesophases may display Grainy-Afosaic,Frond-like (Pseudo-Schlieren), Spherulitic and Oily-Streak birefringenttextures. In some cases where the liquid-crystalline nature of thesample cannot be established unequivocally using polarized-light opticalmicroscopy other well-established. experimental techniques may beutilized. For example, lyotropic mesophases exhibit characteristicquadrupole NMR spectroscopy lineshapes and quadrupole splittings, whilesmall-angle and wide-angle X-ray (or neutron) diffraction measurementsprovide unique and characteristic structured diffraction patterns (referto “Liquid Crystals and Plastic Crystals”, eds. G. W. Gray & P. A.Winsor, Ellis Horwood Ltd., Chichester, UK, 1974, Vols.1 and 2). Suchphase-dependent properties may be used to differentiate, for example, aliquid-crystalline filter dye dispersion from a conventionalmicrocrystalline (i.e.solid) filter dye dispersion.

A particular advantage of the inventive dyes is that in the liquidcrystalline state, they provide higher covering power at their coatingλ_(max) than comparable known dyes which are insoluble and exist asmicrocrystalline solid particles in the photographic medium. Thisadvantage is particularly important in modern film formats andprocessing conditions, as filter dyes with high covering power need notbe coated at as high a coverage as dyes with lower covering power inorder to achieve the same degree of light filtration. In addition toreducing manufacturing costs, lower levels of coated dyes will reducethe level of unwanted dye stain in the processed photographic element,and will reduce the level of dye residue built up in the processingsolutions, and the resulting lower levels of dissolved dye residueremoved from photographic elements will have reduced environmentalimpact.

A further advantage of dyes of the invention is that they generallypossess absorbance envelopes that are sharper cutting on thebathochromic side than typical solid particle dyes. This feature isespecially advantageous when strong light absorbance is required in aspectral region up to a specific λ_(max) and maximum light transmissionis required past the specified λ_(max). Such filter or trimmer dyes areespecially useful when coated in specific layers of color photographicfilms to effectively prevent light of a specific wavelength region fromexposing radiation-sensitive layers below the light filtration layercontaining the dye, but without causing speed losses in the layer belowthe filter dye. A green filter dye coated directly above a red-sensitivesilver halide layer is a particularly advantageous example of suchabsorbance features, and excellent green/red speed separation can berealized. A sharp-cutting bathochromic edge on a filter or trimmer dyeenables excellent color reproduction with minimum speed loss byabsorbing light efficiently up to its absorbance maximum, but verylittle if any just past its absorbance maximum. A magenta trimmer dye(green absorber) which is only moderately sharp-cutting on thebathochromic edge may function adequately as a filter dye, but itsunwanted absorbance in the red region past its λ_(max) will rob thered-sensitive emulsion coated below it of red light and hence speed.In atypical color photographic element, it is desirable to have agreen-absorbing filter dye which when coated absorbs strongly atwavelengths close to 550 nm, but which absorbs comparatively little atwavelengths greater than 550 nm. It should be emphasized that the exactenvelope of desirable light absorbance for a filter dye, evenspecifically a green filter dye, varies tremendously from onephotographic element to another depending on the intended purpose of thematerial. Some photographic elements might require a filter dye, such asa green filter dye, which absorbs strongly up to a wavelength somewhatshorter or longer than 550 nm, but is sharp cutting on the bathochromicside, mostly transmitting wavelengths of light past the desiredabsorbance λ_(max). The feature of coated dye absorbance exhibiting asharp cutting bathochromic and/or hypsochromic characteristic isfundamentally useful for wavelength-specific light filtration, thoughthe exact wavelength of desired spectral shift from absorbance totransmission may be different for different photographic materials.

A further advantage of the dyes of the invention is that in the liquidcrystalline state, many are much sharper absorbing than in theirdissolved isotropic solution state, that is, they possess a muchnarrower halfbandwidth. Furthermore, unlike a dye in the dissolved,isotropic solution state, the dye in the liquid-crystalline state isessentially immobile and not prone to gross diffusion and thus can becoated layer specifically.

The dyes may be located in any layer of the element where it isdesirable to absorb light, but in photographic elements it isparticularly advantageous to locate them in a layer where they will besolubilized and washed out during processing. Useful amounts of dyerange from 1 to 1000 mg/m². The dye should be present in an amountsufficient to yield an optical density at the absorbance D_(max) in thespectral region of interest before processing of at least 0.10 densityunits and preferably at least 0.50 density units. This optical densitywill generally be less than 5.0 density units for most photographicapplications.

The dyes of the invention can be used as interlayer dyes, trimmer dyes,antihalation dyes or light-absorbing elements. They can be used toprevent crossover in X-ray materials as disclosed in U.S. Pat. Nos.4,900,652 and 4,803,150 and European Patent Application Publication No.0 391 405, to prevent unwanted light from reaching a sensitive emulsionlayer of a multicolor photographic element as disclosed in U.S. Pat No.4,988,611, and for other uses as indicated by the absorbance spectrum ofthe particular dye. The dyes can be used in a separate filter layer oras an intergrain absorber.

The liquid crystal-forming dyes of Formula (I-XIII) are useful for thepreparation of radiation sensitive materials. Such materials aresensitive to radiation such as visible light, ultraviolet, infrared, orX-ray.

The liquid crystal-forming dyes of Formula (I-XIII) are also useful innon-photographic imaging elements such as thermally-developableelements, or as dye materials for inkjet applications. Thenon-photographic imaging material may be an optical recording medium,such as a CD or other medium sensitive to a laser, light-emitting diode,or a thermally-developable material.

Another aspect of this invention comprises a radiation sensitive elementcontaining a liquid crystal-forming dye of Formula (I-XIII). Preferably,the radiation sensitive element is a photographic element comprising asupport bearing at least one light sensitive hydrophilic colloid layerand at least one other hydrophilic colloid layer. A dye of FormulaI-XIII may be incorporated in a hydrophilic layer of the photographicelement in any known way.

The support of the element of the invention can be any of a number ofwell-known supports for photographic elements as discussed more fullybelow.

The photographic elements made by the method of the present inventioncan be single color elements or multicolor elements. Multicolor elementscontain dye image-forming units sensitive to each of the three primaryregions of the spectrum. Each unit can be comprised of a single emulsionlayer or of multiple emulsion layers sensitive to a given region of thespectrum. The layers of the element, including the layers of theimage-forming units, can be arranged in various orders as known in theart. In an alternative format, the emulsions sensitive to each of thethree primary regions of the spectrum can be disposed as a singlesegmented layer.

A typical multicolor photographic element comprises a support bearing acyan dye image-forming unit comprised of at least one red-sensitivesilver halide emulsion layer having associated therewith at least onecyan dye-forming coupler, a magenta dye image-forming unit comprising atleast one green-sensitive silver halide emulsion layer having associatedtherewith at least one magenta dye-forming coupler, and a yellow dyeimage-forming unit comprising at least one blue-sensitive silver halideemulsion layer having associated therewith at least one yellowdye-forming coupler. The element can contain additional layers, such asfilter layers, interlayers, overcoat layers, subbing layers, and thelike. All of these can be coated on a support which can be transparentor reflective (for example, a paper support).

Photographic elements of the present invention may also usefully includea magnetic recording material as described in Research Disclosure, Item34390, November 1992, or a transparent magnetic recording layer such asa layer containing magnetic particles on the underside of a transparentsupport as in U.S. Pat. No. 4,279,945 and U.S. Pat. No. 4,302,523. Theelement typically will have a total thickness (excluding the support) offrom 5 to 30 microns. While the order of the color sensitive layers canbe varied, they will normally be red-sensitive, green-sensitive andblue-sensitive, in that order on a transparent support, (that is, bluesensitive furthest from the support) and the reverse order on areflective support being typical.

The present invention also contemplates the use of photographic elementsof the present invention in what are often referred to as single usecameras (or “film with lens” units). These cameras are sold with filmpreloaded in them and the entire camera is returned to a processor withthe exposed film remaining inside the camera. Such cameras may haveglass or plastic lenses through which the photographic element isexposed.

In the following discussion of suitable materials for use in elements ofthis invention, reference will be made to Research Disclosure, September1996, Number 389, Item 38957, which will be identified hereafter by theterm “Research Disclosure I.” The Sections hereafter referred to areSections of the Research Disclosure I unless otherwise indicated. AllResearch Disclosures referenced are published by Kenneth MasonPublications, Ltd., Dudley Annex, 12a North Street, Emsworth, HampshireP010 7DQ, ENGLAND. The foregoing references and all other referencescited in this application, are incorporated herein by reference.

The silver halide emulsions employed in the photographic elements of thepresent invention may be negative-working, such as surface-sensitiveemulsions or unfogged internal latent image forming emulsions, orpositive working emulsions of internal latent image forming emulsions(that are either fogged in the element or fogged during processing).Suitable emulsions and their preparation as well as methods of chemicaland spectral sensitization are described in Sections I through V. Colormaterials and development modifiers are described in Sections V throughXX. Vehicles which can be used in the photographic elements aredescribed in Section II, and various additives such as brighteners,antifoggants, stabilizers, light absorbing and scattering materials,hardeners., coating aids, plasticizers, lubricants and matting agentsare described, for example, in Sections VI through XIII. Manufacturingmethods are described in all of the sections, layer arrangementsparticularly in Section XI, exposure alternatives in Section XVI, andprocessing methods and agents in Sections XIX and XX.

With negative working silver halide a negative image can be formed.Optionally a positive (or reversal) image can be formed although anegative image is typically first formed.

The photographic elements of the present invention may also use coloredcouplers (e.g., to adjust levels of interlayer correction) and maskingcouplers such as those described in EP 213 490; Japanese PublishedApplication 58-172,647; U.S. Pat. No. 2,983,608; German Application DE2,706,117C; U.K. Patent 1,530,272; Japanese Application A-113935; U.S.Pat. No. 4,070,191 and German Application DE 2,643,965. The maskingcouplers may be shifted or blocked.

The photographic elements may also contain materials that accelerate orotherwise modify the processing steps of bleaching or fixing to improvethe quality of the image. Bleach accelerators described in EP 193 389;EP 301 477; U.S. Pat. No. 4,163,669; U.S. Pat. No. 4,865,956; and U.S.Pat. No. 4,923,784 are particularly useful. Also contemplated is the useof nucleating agents, development accelerators or their precursors (UKPatent 2,097,140; U.K. Patent 2,131,188); electron transfer agents (U.S.Pat. Nos. 4,859,578; 4,912,025); antifogging and anti color-mixingagents such as derivatives of hydroquinones, aminophenols, amines,gallic acid; catechol; ascorbic acid; hydrazides; sulfonamidophenols;and non color-forming couplers.

The elements may also contain filter dye layers comprising colloidalsilver sol or yellow and/or magenta filter dyes and/or antihalation dyes(particularly in an undercoat beneath all light sensitive layers or inthe side of the support opposite that on which all light sensitivelayers are located) formulated either as oil-in-water dispersions, latexdispersions, solid particle dispersions, or as direct gelatindispersions. Additionally, they may be used with “smearing” couplers(e.g., as described in U.S. Pat. No. 4,366,237; EP 096 570; U.S. Pat.Nos. 4,420,556; and 4,543,323.) Also, the couplers may be blocked orcoated in protected form as described, for example, in JapaneseApplication 61/258,249 or U.S. Pat. No. 5,019,492.

The photographic elements may further contain other image-modifyingcompounds such as “Developer Inhibitor-Releasing” compounds (DIR's).Useful additional DIR's for elements of the present invention, are knownin the art and examples are described in U.S. Pat. Nos. 3,137,578;3,148,022; 3,148,062; 3,227,554; 3,384,657; 3,379,529; 3,615,506;3,617,291; 3,620,746; 3,701,783; 3,733,201; 4,049,455; 4,095,984;4,126,459; 4,149,886; 4,150,228; 4,211,562; 4,248,962; 4,259,437;4,362,878; 4,409,323; 4,477,563; 4,782,012; 4,962,018; 4,500,634;4,579,816; 4,607,004; 4,618,571; 4,678,739; 4,746,600; 4,746,601;4,791,049; 4,857,447; 4,865,959; 4,880,342; 4,886,736; 4,937,179;4,946,767; 4,948,716; 4,952,485; 4,956,269; 4,959,299; 4,966,835;4,985,336 as well as in patent publications GB 1,560,240; GB 2,007,662;GB 2,032,914; GB 2,099,167; DE 2,842,063, DE 2,937,127; DE 3,636,824; DE3,644,416 as well as the following European Patent Publications:272,573; 335,319; 336,411; 346, 899; 362, 870; 365,252; 365,346;373,382; 376,212; 377,463; 378,236; 384,670; 396,486; 401,612; 401,613.

DIR compounds are also disclosed in “Developer-Inhibitor-Releasing (DIR)Couplers for Color Photography,” C. R. Barr, J. R. Thirtle and P. W.Vittum in Photographic Science and Engineering, Vol. 13, p. 174 (1969),incorporated herein by reference.

It is also contemplated that the concepts of the present invention maybe employed to obtain reflection color prints as described in ResearchDisclosure, November 1979, Item 18716, available from Kenneth MasonPublications, Ltd, Dudley Annex, 12a North Street, Emsworth, HampshireP0101 7DQ, England, incorporated herein by reference. The emulsions andmaterials to form elements of the present invention, may be coated on pHadjusted support as described in U.S. Pat. No. 4,917,994; with epoxysolvents (EP 0 164 961); with additional stabilizers (as described, forexample, in U.S. Pat. Nos. 4,346,165; 4,540,653 and 4,906,559); withballasted chelating agents such as those in U.S. Pat. No. 4,994,359 toreduce sensitivity to polyvalent cations such as calcium; and with stainreducing compounds such as described in U.S. Pat. Nos. 5,068,171 and5,096,805. Other compounds useful in the elements of the invention aredisclosed in Japanese Published Applications 83-09,959; 83-62,586;90-072,629, 90-072,630; 90-072,632; 90-072,633; 90-072,634; 90-077,822;90-078,229; 90-078,230; 90-079,336; 90-079,338; 90-079,690; 90-079,691;90-080,487; 90-080,489; 90-080,490; 90-080,491; 90-080,492; 90-080,494;90-085,928; 90-086,669; 90-086,670; 90-087,361; 90-087,362; 90-087,363;90-087,364; 90-088,096; 90-088,097; 90-093,662; 90-093,663; 90-093,664;90-093,665; 90-093,666; 90-093,668; 90-094,055; 90-094,056; 90-101,937;90-103,409; 90-151,577.

The silver halide used in the photographic elements may be silveriodobromide, silver bromide, silver chloride, silver chlorobromide,silver chloro iodobromide, and the like. For example, the silver halideused in the photographic elements of the present invention may containat least 90% silver chloride or more (for example, at least 95%, 98%,99% or 100% silver chloride). In the case of such high chloride silverhalide emulsions, some silver bromide may be present but typicallysubstantially no silver iodide. Substantially no silver iodide means theiodide concentration would be no more than 1%, and preferably less than0.5 or 0.1%. In particular, in such a case the possibility is alsocontemplated that the silver chloride could be treated with a bromidesource to increase its sensitivity, although the bulk concentration ofbromide in the resulting emulsion will typically be no more than about 2to 2.5% and preferably between about 0.6 to 1.2% (the remainder beingsilver chloride). The foregoing % figures are mole %.

The type of silver halide grains preferably include polymorphic, cubic,and octahedral. The grain size of the silver halide may have anydistribution known to be useful in photographic compositions, and may beeither polydispersed or monodispersed.

Tabular grain silver halide emulsions may also be used. Tabular grainsare those with two parallel major faces each clearly larger than anyremaining grain face and tabular grain emulsions are those in which thetabular grains account for at least 30 percent, more typically at least50 percent, preferably >70 percent and optimally >90 percent of totalgrain projected area. The tabular grains can account for substantiallyall (>97 percent) of total grain projected area. The tabular grainemulsions can be high aspect ratio tabular grain emulsions—i.e.,ECD/t >8, where ECD is the diameter of a circle having an area equal tograin projected area and t is tabular grain thickness; intermediateaspect ratio tabular grain emulsions—i.e., ECD/t=5 to 8; or low aspectratio tabular grain emulsions—i.e., ECD/t=2 to 5. The emulsionstypically exhibit high tabularity (T), where T (i.e., ECD/t²)>25 and ECDand t are both measured in micrometers (mm). The tabular grains can beof any thickness compatible with achieving an aim average aspect ratioand/or average tabularity of the tabular grain emulsion. Preferably thetabular grains satisfying projected area requirements are those havingthicknesses of <0.3 mm, thin (<0.2 mm) tabular grains being specificallypreferred and ultrathin (<0.07 mm) tabular grains being contemplated formaximum tabular grain performance enhancements. When the native blueabsorption of iodohalide tabular grains is relied upon for blue speed,thicker tabular grains, typically up to 0.5 mm in thickness, arecontemplated.

High iodide tabular grain emulsions are illustrated by House U.S. Pat.No. 4,490,458, Maskasky U.S. Pat. No. 4,459,353 and Yagi et al EPO 0 410410.

Tabular grains formed of silver halide(s) that form a face centeredcubic (rock salt type) crystal lattice structure can have either {100}or {111 } major faces. Emulsions containing {111} major face tabulargrains, including those with controlled grain dispersities, halidedistributions, twin plane spacing, edge structures and graindislocations as well as adsorbed {111} grain face stabilizers, areillustrated in those references cited in Research Disclosure I, SectionI.B.(3) (page 503).

The silver halide grains to be used in the invention may be preparedaccording to methods known in the art, such as those described inResearch Disclosure I and James, The Theory of the Photographic Process.These include methods such as ammoniacal emulsion making, neutral oracidic emulsion making, and others known in the art. These methodsgenerally involve mixing a water soluble silver salt with a watersoluble halide salt in the presence of a protective colloid, andcontrolling the temperature, pAg, pH values, etc, at suitable valuesduring formation of the silver halide by precipitation.

The silver halide to be used in the invention may be advantageouslysubjected to chemical sensitization with noble metal (for example, gold)sensitizers, middle chalcogen (for example, sulfur) sensitizers,reduction sensitizers and others known in the art. Compounds andtechniques useful for chemical sensitization of silver halide are knownin the art and described in Research Disclosure I and the referencescited therein.

The photographic elements of the present invention, as is typical,provide the silver halide in the form of an emulsion. Photographicemulsions generally include a vehicle for coating the emulsion as alayer of a photographic element. Useful vehicles include both naturallyoccurring substances such as proteins, protein derivatives, cellulosederivatives (e.g., cellulose esters), gelatin (e.g., alkali-treatedgelatin such as cattle bone or hide gelatin, or acid treated gelatinsuch as pigskin gelatin), gelatin derivatives (e.g., acetylated gelatin,phthalated gelatin, and the like), and others as described in ResearchDisclosure I. Also useful as vehicles or vehicle extenders arehydrophilic water-permeable colloids. These include synthetic polymericpeptizers, carriers, and/or binders such as poly(vinyl alcohol),poly(vinyl lactams), acrylamide polymers, polyvinyl acetals, polymers ofalkyl and sulfoalkyl acrylates and methacrylates, hydrolyzed polyvinylacetates, polyamides, polyvinyl pyridine, methacrylamide copolymers, andthe like, as described in Research Disclosure I. The vehicle can bepresent in the emulsion in any amount useful in photographic emulsions.The emulsion can also include any of the addenda known to be useful inphotographic emulsions. These include chemical sensitizers, such asactive gelatin, sulfur, selenium, tellurium, gold, platinum, palladium,iridium, osmium, rhenium, phosphorous, or combinations thereof. Chemicalsensitization is generally carried out at pAg levels of from 5 to 10, pHlevels of from 5 to 8, and temperatures of from 30 to 80° C., asdescribed in Research Disclosure I, Section IV (pages 510-511) and thereferences cited therein.

The silver halide may be sensitized by sensitizing dyes by any methodknown in the art, such as described in Research Disclosure I. The dyemay be added to an emulsion of the silver halide grains and ahydrophilic colloid at any time prior to (e.g., during or after chemicalsensitization) or simultaneous with the coating of the emulsion on aphotographic element. The dyes may, for example, be added as a solutionin water or an alcohol. The dye/silver halide emulsion may be mixed witha dispersion of color image-forming coupler immediately before coatingor in advance of coating (for example, 2 hours).

Photographic elements of the present invention are preferably imagewiseexposed using any of the known techniques, including those described inResearch Disclosure I, section XVI. This typically involves exposure tolight in the visible region of the spectrum, and typically such exposureis of a live image through a lens, although exposure can also beexposure to a stored image (such as a computer stored image) by means oflight emitting devices (such as light emitting diodes, CRT and thelike).

Photographic elements comprising the composition of the invention can beprocessed in any of a number of well-known photographic processesutilizing any of a number of well-known processing compositions,described, for example, in Research Disclosure I, or in T. H. James,editor, The Theory of the Photographic Process, 4th Edition, Macmillan,N.Y., 1977. In the case of processing a negative working element, theelement is treated with a color developer (that is one which will formthe colored image dyes with the color couplers), and then with aoxidizer and a solvent to remove silver and silver halide. In the caseof processing a reversal color element, the element is first treatedwith a black and white developer (that is, a developer which does notform colored dyes with the coupler compounds) followed by a treatment tofog silver halide (usually chemical fogging or light fogging), followedby treatment with a color developer. Preferred color developing agentsare p-phenylenediamines. Especially preferred are:

4-amino N,N-diethylaniline hydrochloride,

4-amino-3-methyl-N,N-diethylaniline hydrochloride,

4-amino-3-methyl-N-ethyl-N-(b-(methanesulfonamido) ethylanilinesesquisulfate hydrate,

4-amino-3-methyl-N-ethyl-N-(b-hydroxyethyl)aniline sulfate,

4-amino-3-b-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochlorideand

4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonicacid.

Development is followed by bleach-fixing, to remove silver or silverhalide, washing and drying.

Synthesis of Dye 1-1A

6-chloro-benzothiophene dioxide (10 g, 46.3 mmol)anddiethoxymethylacetate (7.5 g, 46.3 mmol)were suspended in 150 mlacetonitrile at 25C. Triethylamine (14 g, 139 mmol) was added over 5 minproducing a golden yellow solution which was stirred 60 min. The dyesolution was poured into excess diethyl ether and the resulting solidwas collected by filtration. Isolatecl 10.7 g (87%) of the dye as ayellow solid. All analytical data were consistent with the structure.

Synthesis of Dye 2-1A

6-chloro-benzothiophene dioxide (10 g, 46.3 mmol)and trimethoxypropene(6.1 g, 46.3 mmol)were suspended in 200 ml ethanol at 25C. Triethylamine(14 g, 139 mmol) was added over 5 min. The mixture was heated to refluxand held for 30 min. A red solid precipitated from the hot reactionmixture. The mixture was then allowed to cool to 25° C., and theprecipitated dye was collected by filtration and washed with ethanol.The collected solid was suspended in 100 mL acetonitrilel and heated toreflux while 1 mL concentrated HCl was added over 5 min. The resultingslurry was heated at reflux for 10 min, then allowed to cool to 25° C.The dye was collected by filtration, washed with acetonitrile and dried.Isolated 7.8 g (72%) of Dye 6 as a red/orange solid. All analytical dalawere consistent with the structure.

Synthesis of Dye 6-1

Triethylamine (2.5 g, 0.025 mol) was added in one portion to a stirringslurry of 6-methoxy-2-phenyl-1,3,3-tricyanohexatriene (5 g, 0.02 mol)and 5-phenyl-2-methyl-3-sulfopropylbenzoxozole (6.6 g, 0.02 mol) in 40mL absolute ethanol at 25C. The reaction mixture was heated to refluxand held for 30 minutes, then allowed to cool to 25C with stirring. Theprecipitated product was collected by filtration and rinsed withethanol. The crude dye was slurried in ethanol at reflux, then cooled to25C, then collected by filtration to afford 8.6 g (65% yield) of thepure dye 6-1. All analytical data was consistent with the assignedstructure.

EXPERIMENTAL EXAMPLES Formulation A: Solid Particle Dispersion (SPD)Formulation Procedure

Step 1:

Dyes were formulated as aqueous dye by ball-milling according to thefollowing procedure. Water (22.0 g) and a 10.0% solution of TritonX-200®, an alkyl aryl polyether sulfonate surfactant available from Rohmand Haas, (1.0 g) were placed in a 120 mL screw-capped bottle. A 1.0 gsample of dye was added to this solution. Zirconium oxide beads (60 mL,1.8 mm diameter) were added and the container with the cap tightlysecured was placed in a mill and the contents milled for four days. Theresulting mixture was then filtered to remove the zirconium oxide beads.The resulting aqueous dye slurries were dispersed into gelatin asdescribed in Step 2.

Step 2

Aqueous gelatin dispersions of the above dye slurries (step 1) wereprepared as follows. The vessel containing the dye slurry was removedand a known weight of dye slurry was added to a 12.5% aqueous gelatinsolution (18.0 g) at 45-80° C. This mixture was then diluted with waterto a weight of 88.87 g., yielding the final dye dispersion. In thesubsequent experimental sections gelatin-containing dye dispersionsprepared in this manner will be referred to as Formulation A. The term“SPD” is used throughout simply to denote dye dispersions which havebeen formulated using well known milling techniques normally used forpreparing solid particle microcrystalline dye dispersions. This does notimply that the physical state of the dye prepared in this manner isexclusively microcrystalline in nature.

The dispersions described above may be prepared at a wide variety of dyeconcentrations ranging from 0.005-30% w/w. The most commonly employedconcentrations were 0.01-0.30% dye.

Formulation B: Direct Gelatin Dispersion (DGD) Formulation Procedure

Nominally 2.000 g H₂O then 0.12500 g deionized gelatin were weighed intoscrew-topped glass vials and allowed to soak at 25° C. for at least 30minutes. The swollen gelatin was then melted at 50° C. for 15 minuteswith agitation. The gelatin solution was cooled to 25° C., thenrefrigerated at 5° C. to set. Nominally 2.870 g H₂O was then added ontop of the set gelatin followed by 0.00500 g of powdered dye. The dyepowder was thoroughly wetted and dispersed in the water layer byagitation and then allowed to stand at 25° C. for 17 hours. The sampleswere then heated to 60-80° C. in a water bath for 1-2 hours and mixedwith intermittent agitation. The samples were subsequently cooled to39.0° C. over a period of approximately 1 hour and maintained at thistemperature until measurement. In the subsequent experimental sectionsdispersions prepared in this manner will be referred to as Formulation B(direct gel dispersions or DGD's).

The above formulation corresponds to a dye concentration 0.10% w/w, butthe dispersions may be prepared at a wide variety of dye concentrationsranging from 0.005-30% w/w. The most commonly employed dyeconcentrations were 0.01-0.30% w/w. In some instances, regularlime-processed photographic gelatin (non-decalcified). was used inpreference to deionized (decalcified) gelatin.

Example 1

Polarized-Light Optical Microscopy Test for Formation of Dye LyotropicLiquid Crystalline Phases (Liquid Crystal Phase Test)

Direct aqueous gelatin dispersions (DGD's) of known composition wereprepared as described for FormulationB for the inventive dyes and thecomparitive dyes and allowed to cool to room temperature to set. Smallaliquots of the gelled dye dispersions were then removed from the glassvials and sandwiched between a pre-cleaned glass micro slide (Gold SealProducts, USA) and a micro cover glass (VWR Scientific, USA) to form athin film. Each slide was then viewed in polarized-light at amagnification of 16× objective using a Zeiss Universal M microscopefitted with polarizing elements.

Liquid-crystalline DGD's were readily identified by their birefringent(bright) characteristic type-textures and interference colours whenviewed in polarized light. Isotropic DGD's (solution dye, non-liquidcrystalline) were readily distinguishable from liquid-crystalline DGD'sby their complete lack of birefringency (i.e. black appearance) whenviewed in polarized light. Crystalline DGD's (solid dye, non-liquidcrystalline) were readily distinguishable from isotropic andliquid-crystalline DGD's due to the presence of finite-sized solid dyeparticles or crystals, or clumps of such solid particles or crystals,which were not readily deformable with moderate shear when pressure wasapplied to the cover glass. The gelled DGD's were then heated throughthe gel to sol transition (40°-50° C.) while observing the sample slidemicroscopically in polarized light. Dyes forming a lyotropic nematicmesophase typically displayed characteristic fluid, viscoelastic,birefringent textures including so-called Schlieren, Tiger-Skin,Reticulated, Homogeneous (Planar), Thread-Like, Droplet and Homeotropic(Pseudoisotropic). Dyes forming a lyotropic hexagonal mesophasetypically displayed viscous, birefringent Herringone, Ribbon or Fan-Liketextures. Dyes forming a lyotropic smectic mesophase displayed so-calledGrainy-Mosaic, Spherulitic, Frond-Like (F'seudo-Schlieren) andOily-Streak birefringent textures.The most preferred liquidcrystal-forming dyes of the invention clearly remained in aliquid-crystalline state at these elevated temperatures as evidencedfrom their characteristic birefringent type-textures and rheology. Insome instances, the dye liquid crystal phase melted reversibly to theisotropic dye solution phase (non-birefringent) on heating. In someinstances, the dye liquid crystal phase co-existed with solid dye. Bymaintaining the sample slide at an elevated temperature, the presenceand stability of the dye mesophase(s) could be monitored duringperipheral evaporation of the solvent to a more concentrated evaporated(dried-down) state. The most preferred dyes of the invention exhibitedmicroscopic liquid-crystalline textures in the wet gelled state, the wetmelt (sol) state and the evaporated (dried-down) state. These states(gelled, sol and evaporated) are denoted in Table 16, column 4 by theletters g, s and e in parenthesis. The dye and gelatin concentrationsrefer to the samples in the wet gelled and sol states, beforeevaporation. For some of the inventive dyes, aqueous dye dispersions ofknown composition (without gelatin) were prepared by mixing the powdereddye into water at 60° C. for 1 hour with agitation, then cooling to roomtemperature before microscopic examination.

Preferred dyes of the invention formed lyotropic liquid-crystallinephases in aqueous media at dye concentrations of ≦30% w/w, morepreferred dyes formed lyotropic liquid-crystalline phases atconcentrations of ≦10% w/w dye, even more preferred dyes formedlyotropic liquid-crystalline phases at concentrations of ≦5% w/w dye,and the most preferred dyes formed lyotropic liquid-crystalline phasesat concentrations of ≦0.5% w/w. Representative data are summarized inTable 16 below.

TABLE 16 Dye Conc. Dye # (% w/w) Solvent* Liquid Crystal Phase†  1-10.10 D.G  smectic (g, s, e)  1-1A 0.10 D.G. smectic (g, s, e)  1-2 0.20D.G. smectic (e)  1-2A 0.20 D.G. smectic (g, s, e)  1-3 0.10 D.G.smectic (g, s, e)  1-4 0.10 D.G. smectic (g, s, e)  1-5 0.21 D.G.smectic (e)  2-1 0.25 D.G. smectic (g, e)  2-1A 0.05 D.G. smectic (g, s,e)  2-2 0.15 D.G. smectic (e)  2-3 0.10 D.G. nematic (g, s, e)  2-4 0.06D.G. smectic (g, e)  2-6 0.15 D.G. smectic (e)  3-1 0.22 D.G. nematic(g, e)  3-2 0.10 D.G. nematic (g, s, e)  5-1 0.10 D.G. smectic (g, s, e) 5-2 0.10 D.G. smectic (g, s, e)  5-3 0.10 D.G. smectic (g, s, e)  5-40.10 D.G. smectic (g, s, e)  5-5 0.10 D.G. smectic (g, e)  5-6 0.06 D.G.smectic (g, s, e)  5-7 0.10 D.G. smectic (g, s, e)  5-15 0.15 D.G.smectic (g, s, e)  5-16 0.10 D.G. smectic (e)  5-17 0.10 D.G. smectic(g, s, e)  5-21 0.10 D.G. smectic (g, s, e)  5-23 0.06 D.G. smectic (g,s, e)  5-24 0.06 D.G. smectic (g, s, e)  5-27 0.04 D.G. smectic (g, s,e)  6-1 0.10 D.G. smectic (g, s, e)  6-2 0.12 D.G. nematic (g, s, e) 6-3 0.10 D.G. smectic (g, s, e)  6-4 0.10 D.G. smectic (g, e)  6-5 0.10D.G. smectic (g, s, e)  6-7 0.11 D.G. nematic (g, s, e)  6-13 0.12 D.G.smectic (g, s, e)  7-1 0.10 D.G. smectic (g, s, e)  7-3 0.11 D.G.nematic (g, s, e)  7-3 5.0 water nematic  8-1 0.20 R.G. smectic (g, s,e)  8-4 10.0 water nematic  8-7 0.30 D.G. smectic (e)  9-4 0.31 D.G.nematic (g, e) 10-6 0.10 D.G. nematic (g, s, e) 10-10 0.10 D.G. smectic(g, s, e) 11-2 0.10 D.G. nematic (g, e) 11-2 0.20 R.G. nematic (g, s, e)11-4 0.10 D.G. smectic (g, s, e) 11-11 0.13 D.G. nematic (g, s, e) 11-1420.0 water hexagonal 12-5 0.10 D.G  nematic (g, s, e) 12-1 0.10 D.G.nematic (g, s, e) 12-1 0.11 R.G. nematic (g, s, e) 12-2 0.10 D.G.smectic (g, s, e) 12-4 0.13 D.G. smectic (g, s, e) 13-1 0.11 D.G.smectic (g, s, e) 13-4 0.04 D.G. smectic (g, s, e) 13-11 0.10 D.G.nematic (g, s, e) 14-1 0.11 D.G. nematic (g, e) 14-1 0.10 R.G. nematic(g, s, e) 14-2 0.10 D.G. smectic (g, s, e) 14-3 0.10 R.G. smectic (g, s,e) 14-4 0.20 R.G. nematic (g, s, e) 15-1 0.08 D.G. smectic (g, e) A 0.15D.G. none apparent (g, s, e) B 0.13 D.G. none apparent (g, s, e) C 0.16D.G. none apparent (g, s, e) D 0.21 D.G. none apparent (g, s, e) E 0.30D.G. none apparent (g, s, e) F 0.10 D.G. none apparent (g, s, e) G 0.10D.G. none apparent (g, s, e) H 0.10 D.G. none apparent (g, s, e) I 0.12D.G. none apparent (g, s, e) J 0.10 D.G. none apparent (g, s, e) K 0.11D.G. none apparent (g, s, e) *D.G. = 2.5% w/w aqueous Deionized (i.e.decalcified) Gelatin; R.G. = 2.5% w/w aqueous Regular (non-decalcified)Gelatin. †The letters g, s and e refer to samples in the gelled, sol andevaporated states.

COMPARATIVE DYES Comparative Dye A

Comparative Dye B

Comparative Dye C

Comparative Dye D

Comparative Dye E

Comparative Dye F

Comparative Dye G

Comparative Dye H

Comparative Dye I

Comparative Dye J

Comparative Dye K

Example 2

Absorption wavelength λ_(max)), Halfbandwidth (Hbw) and Molar ExtinctionCoefficients (λ_(max)) of Wet Dye DGD's (Spectral Properties of TypicalSmectic Liquid Crystals of Dyes).

Direct gelatin dispersions (DGD's) of Dyes 1—1, 1-1A, 1-4, 2-1A, 2-4,5-2 to 5-4, 5-6, 5-7, 5-23, 5-24, 6-1, 6-3 to 6-5, 6-13, 11-5, 13—13,15-1 and Comparative Dyes A-C and E-F were prepared as described forFormulationB. Aliquots of each dispersion, held at 39° C., weretransferred to 0.0066 cm pathlength glass cells and their absorptionspectra measured at 25° C. These wet dispersions are referred to as “wetDGD's”. Solutions of Dyes 1—1, 1-1A, 1-4, 2-1A, 2-4, 5-2 to 5-4, 5-6,5-7, 5-23, 5-24, 6-1, 6-3 to 6-5, 6-13, 11-4, 12-4, 13-1, 13-4, 13-5,13—13, 15-1 and Comparative Dyes A-C and E-F were prepared in a suitableorganic solvent (methanol or methanol with added triethylamine unlessotherwise noted) and their absorption spectra measured at 25° C. Theextinction coefficients for the isotropic dye solutions and dye wetDGD's were calculated according to Beer's Law, and halfbandwidths (Hbw)measured. The data are summarized in Table 17.

TABLE 17 λ_(max) λ_(max) DGD Hbw λ_(max) λ_(max) soln. Hbw DGD Wt % Dye(wet) DGD soln. (mol⁻¹ soln. (wet) in wet (mol⁻¹ (wet) Dye (nm) 1 cm⁻¹)× 10⁴ (nm) (nm) DGD 1 cm⁻¹) × 10⁴ (nm) 1-1 447 4.7 57 489 0.08 15.9 121-1A 447 4.8 56 489 0.10 19.3 12 1-4 450 3.9 61 486 0.10 12.2 16 2-1A552 11.8 57 611 0.05 36.3 22 2-4 542 10.4 54 614 0.06 14.2 12 5-2 49811.2 41 560 0.06 32.3 17 5-3 502 9.8 45 554 0.04 30.9 21 B23193 5-4 50010.1 42 561 0.06 34.6 17 B23252 5-6 502 13.5 44 557 0.04 55.0 19 B232865-7 511 9.9 55 550 0.08 22.7 43 B23165 5-23 502 12.2 45 557 0.06 28.7 19B23116 5-24 501 12.1 44 551 0.04 49.6 19 B23114 6-1 599 16.4 56 681 0.0633.6 16 B21655 6-3 606 19.1 47 689 0.04 47.4 38 B22134 6-4 607 11.1 82666 0.04 44.2 33 B23166 6-5 584 12.5 68 684 0.06 32.1 36 B22019 6-13 60312.2 78 680 0.04 52.3 33 11-4 444 8.7 39 474 0.08 21.7 17 B23249 12-4566 12.7 44 638 0.06 45.2 21 13-1 579 6.7 69 628 0.06 43.8 19 13-4 5757.3 70 629 0.06 42.9 19 13-13 577 14.4 63 625 0.04 26.7 33 14-2 450 5.463 449 0.10 5.3 100  15-1 472 3.5 76 556 0.08 5.6 19 A 442 3.5 56 4390.10 6.8 59 B 550 10.8 56 537 0.13 10.1 74 C 643 14.0 66 639 0.10 10.7141  E 499 11.5 41 497 0.04 6.3 52 F 598 8.5 54 589 0.06 5.3 84

The above results demonstrate that the direct gelatin dispersionscontaining the inventive dyes, dispersed in a smectic liquid-crystallinestate, exhibit bathochromically or hypsochromically-shifted absorptionmaxima relative to their isotropic solution (i.e. monomeric) absorptionmaxima. Moreover, the inventive dyes, when formulated as wetliquid-crystalline DGD's, exhibit higher extinction coefficients andnarrower halfbandwidths compared to their non liquid-crystalline,isotropic solution states in a solvent such as methanol. Moreover, aswet liquid-crystalline DGD's the inventive dyes are far superior in bothHbw and extinction coefficient to the comparative non liquid-crystallinedyes A-C and E-F.

Example 3

Dye Wandering Properties

Direct gelatin dispersion melts (Wet DGD's) were prepared for Dyes 1—1,1-2, 5-2, 5-3, 5-6, 5-24, 6-1, 6-3, 6-7, 7-3, 11-4, 12-1, 12-4, 13-1,14-1,14-2, 14-4, 15-1 and Comparative Dyes A, B, E and F as describedfor Formulation B (wt % dye 0.06-0.1). Aqueous gelatin melts containingno dye were prepared as a receiver layer and chill set detailformulation specs, i.e. wt % gel=2.5%). The set gelatin receiver padswere allowed to equilibrate at 25C. The wet DGD melts (held at 39C) werepipeted atop the gelatin receiver pads and allowed to sit for 24 hr.Observed color in the bottom layer representing solubilized, mobile dyewas recorded after 2 hours and 24 hours on a scale of 0 to 5 with 0being no color observed migrating and 5 meaning that the upper and lowerlayers appeared identical in color (full equilibration). Observationsare recorded in Table 18.

TABLE 18 Liquid crystal phase Observed Color Observed Color (microscopy)after 1 hour after 24 hours Dye (from Table 16) (0 to 5) (0 to 5)  1-1smectic 1 2  1-2 smectic 1 2  5-2 smectic 0 1  5-3 smectic 0 0  5-6smectic 0 1  5-24 smectic 0 0  6-1 smectic 0 0  6-3 smectic 0 0  6-7nematic 0 0  7-3 nematic 1 3 11-4 smectic 1 2 12-1 nematic 0 1 12-4smectic 0 0 13-1 smectic 0 0 14-1 nematic 1 2 14-2 smectic 1 2 14-4nematic 0 1 15-1 smectic 1 1 A none 2 3 B none 2 5 E none 2 4 F none 3 5

The above data clearly demonstrate that the inventive liquidcrystal-forming dyes, whether nematic or smectic in nature, remainlargely, and in some cases completely immobile when coated, and do notappreciably migrate from the layer in which they are coated. Bycontrast, the comparative dyes migrate freely from the layer in whichthey are coated to adjacent layers. This example demonstrates afundamental advantage of the inventive liquid crystal-forming dyes oversoluble dyes widely used in the art.

Example 4

Absorption wavelength (λ_(max)), Halfbandwidth (Hbw) and MolarExtinction Coefficients (λ_(max)) of Wet Dye DGD's (Spectral Propertiesof Typical Nematic Liquid Crystals).

Direct gelatin dispersions (DGD's) of Dyes 2-3, 6-7, 7-3, 10-6, 11—11,12-1, 13-11, 14-1, 14-4 and Comparative Dyes A-C and E-F were preparedas described for Formulation B. Aliquots of each dispersion, held at 39°C., were transferred to 0.0066 cm pathlength glass cells and theirabsorption spectra measured at 25° C. These wet dispersions are referredto as “wet DGD's”. Solutions of Dyes and Comparative Dyes A-B and E-Fwere prepared in a suitable organic solvent (methanol or methanol withadded triethylamine unless otherwise noted) and their absorption spectrameasured at 25° C., and their halfbandwidths (Hbw) measured. The dataare summarized in Table 19.

TABLE 19 λ_(max) λ_(max) DGD Hbw λ_(max) λ_(max) soln. Hbw DGD Wt % Dye(wet) DGD soln. (mol⁻¹ soln. (wet) in wet (mol⁻¹ (wet) Dye (nm) 1 cm⁻¹)× 10⁴ (nm) (nm) DGD 1 cm⁻¹) × 10⁵ (nm) 2-3 548 10.7 56 614 0.10 17.0 176-7 636 18.0 51 599 0.10 14.4 48 7-3 533 11.25 52 549 + 627 0.20 >9.3 3410-6 439 8.05 56 432 0.20 7.6 52 11-1 560 11.9 55 490 + 576 0.10 >6.9152  12-1 541 13.7 44 576 + 538 0.10 >5.8 82 13-11 474 8.1 61 480 0.2010.1 67 14-1 460 5.1 65 428 0.20 6.3 59 14-4 510 6.7 70 454 0.20 5.0 55A 442 5.7 56 448 0.13 6.8 52 B 550 10.8 56 537 0.13 10.1 74 E 499 11.541 497 0.04 6.3 52 F 601 8.5 54 589 0.06 5.3 84

The above results demonstrate that the direct gelatin dispersionscontaining some of the inventive nematic liquid crystal-forming dyesdisplay a wider range of spectral properties than the smectic liquidcrystal-forming dyes of the previous example. These properties rangefrom clearly advantaged in terms of extinction coefficient andhalflbandwidth to somewhat disadvantaged relative to the correspondingisotropic solution. However, the inventive liquid crystal-forming dyesof this example all possess the superior property of being slow ornon-diffusing in coated layers as compared with the monomeric(non-liquid crystalline) comparative dyes (see Example 3), an importantphysical property typical of liquid crystal phases.

Example 5

Spectral Properties of Evaporated Dye DGD Coatings.

Direct gelatin dispersions (DGD's) of Dyes 1—1 to 1-5, 2-1 to 2-4, 2-6,3-1, 4-3, 5-1 to 5-7, 5-15 to 5-17, 5-21, 5-23, 5-24, 5-27, 6-1 to 6-5,6-13, 7-1, 8-1, 8-1, 8-7, 10-1,10—10, 11-1, 11-2, 11-4, 12-4, 13-1,13-4, 13-5, 13—13, 15-1 and Comparative Dyes A-F were prepared usingpowdered dye as described for FormulationB. Aliquots of each dispersion,held at 39° C., were then smeared onto standard glass microscope slides(0.8/1.0 mm thickness) to form uniformly thin wet films which wereallowed to dry at ambient temperature and humidity for at least 17 hourssuch that their D_(max)(evap) was less than 4.0 absorbance units. Theabsorption spectra for these evaporated gelatin films were then measuredat 25° C. These samples are referred to in Table 20 as “evap DGD's”.Solutions for each of the above listed dyes were prepared in a suitableorganic solvent (methanol or methanol with added triethylamine unlessotherwise noted) and their absorption spectra measured at 25° C. Foreach dye, the difference in absorbance maxima between the coated dye andthe dye dissolved in a solvent (Δλ_(max)=(λ_(max)DGD_(evap)−λ_(max soln))), and the difference in halfbandwidth betweenthe coated dye and the dye dissolved in a solvent (ΔHbw=Hbw Evap DGD−Hbwsoln) were calculated. The data are summarized in Table 20.

TABLE 20 λ_(max) λ_(max) Evap Hbw Hbw Δ soln. DGD soln Evap λ_(max) ΔHbwDye (nm) (nm) (nm) (nm) (nm) (nm) 1-1 447 488 57 15 +38 −42 1-1A 447 48756 14 +40 42 1-2 439 476 53 13 +37 40 1-2A 434 477 51 13 +43 −38 1-3 454483 53 14 +29 −39 1-4 450 486 61 21 +36 −40 1-5 447 476 55 19 +29 −362-1 552 610 58 19 +58 −39 2-1A 552 610 57 21 +58 −36 2-3 548 610 56 18+62 −38 2-4 542 609 54 15 +67 −39 2-6 543 624 39 12 +81 −27 3-1 670 48758 24 −183 −34 4-3 677 804 78 21 +127 −57 5-1 495 545 43 23 +50 −20 5-2498 561 41 19 +63 −21 5-3 502 553 45 22 +51 −23 5-4 500 554 44 24 +54−20 5-5 506 562 46 20 +56 −26 5-6 502 555 44 17 +53 −27 5-7 511 551 5539 +40 −16 5-15 533 599 42 31 +66 −11 5-16 549 616 57 25 +67 −32 5-17536 600 44 31 +64 −13 5-21 495 552 42 44 +57  +2 5-23 501 552 44 21 +51−23 5-24 502 556 45 20 +54 −25 5-27 537 611 39 17 +74 −22 6-1 599 684 5624 +85 −32 6-2 592 677 56 40 +75 −16 6-3 606 688 47 46 +60  −1 6-4 607670 82 31 +63 −51 6-5 584 684 68 36 +100 −32 6-13 603 682 78 27 +79 −517-1 631 472 58 12 −159 −46 8-1 455 503 52 61 +48  +9 B23209 8-7 640 72480 49 +84 −31 10-1 430 465 48 47 +35  −1 10-10 438 454 52 19 +16 −3311-1 437 443 51 40 +6 −11 11-2 444 469 39 48 +25 −11 11-4 444 477 39 19+33 −20 12-4 560 637 44 21 +77 −23 13-1 579 630 69 20 +51 −49 13-4 575630 70 20 +55 −50 13-5 572 641 64 14 +69 −50 13-13 577 625 63 33 +48 −3015-1 472 552 76 20 +80 −56 B22527-Na A 442 450 56 55 +8  −1 B 550 553 5665 +3  +9 C 643 657 66 106  +14 +40 D 662 671 66 50 +9 −16 E 499 508 4172 +9 +31 F 601 606 53 92 +5 +39

The above results clearly demonstrate the useful spectral features ofthe inventive liquid crystal-forming dyes in evaporated coatingsrelative to the spectral features exhibited in their solution state. Thecoated inventive dyes exhibit absorbance maxima which are significantlybathochromic or hypsochromic, and halfbandwidths (Hbw) which aresignificantly narrower than those of the dyes dissolved in solvent (nonliquid-crystalline). It is also clear from the above data that the thecoated comparative dyes A-F exhibit no comparable advantageous spectralchanges relative to their dissolved solution state.

Example 6

Spectral Properties of Wet and Evaporated Dye DGD's.

Direct gelatin dispersions (DGD's) of Dyes 1—1 to 1-5, 2-1, 2-1A, 2-3,2-4, 2-6, 3-1, 5-1 to 5-4, 5-6, 5-7, 5-16, 5-23, 5-24, 6-1, 6-3 to 6-5,6-13, 7-1, 11-4, 12-4, 13-1, 13-4, 13-3, 15-1 and Comparative Dyes A-Cand E-F were prepared using powdered dye as described for FormulationB.Aliquots of each dispersion, held at 39° C., were transferred to 0.0066cm pathlength glass cells and their absorption spectra measuredimmediately at 25° C. These samples are referred to in Table 21 as “wetDGD's”. Solution aliquots of each dispersion were also smeared ontostandard glass microscope slides (0.8/1.0 mm thickness) to formuniformly thin wet films which were allowed to dry at ambienttemperature and humidity for at least 17 hours such that theirD_(max)(evap) was less than 4.0 absorbance units. The absorption spectrafor these evaporated gelatin films were then measured at 25° C. Thesesamples are referred to in Table 21 as “Evap DGD”. The data aresummarized in Table 21.

TABLE 21 λ_(max) λ_(max) Evap Hbw Hbw Wet DGD DGD Wet Evap Dye (nm) (nm)(nm) (nm)  1-1 489 488 12 15  1-1A 489 487 12 14  1-2 434 476 55 13 1-2A 480 + 441 477 58 13  1-3 484 + 457 483 55 14  1-4 486 486 16 21 1-5 445 476 59 19  2-1 546 + 611 610 >100 19  2-1A 611 610 22 18  2-3614 610 17 18  2-4 614 609 12 15  2-6 503 + 617 624 57 12  3-1 563 + 490487 135 24  5-1 544 + 497 544 57 24  5-2 560 561 17 19  5-3 554 553 2122  5-4 560 554 17 24  5-6 557 555 19 17  5-7 550 551 43 39  5-16 552 +611 616 86 25  5-23 557 552 19 21  5-24 551 556 19 20  6-1 681 684 16 24 6-3 689 688 38 46  6-4 666 670 33 31  6-5 684 684 36 36  6-13 680 68233 27  7-1 474 472 22 12 11-4 474 477 17 19 12-4 638 637 21 21 13-1 628630 19 20 13-4 629 630 19 20 13-3 624 625 33 33 15-1 556 + 487 552 19 20A 448 450 52 54 B 537 553 74 65 C 636 657 135 106 E 497 508 52 72 F 589606 84 92

The above results clearly demonstrate that the useful spectral featuresof bathochromic absorbance maximum and narrow halfbandwidth for eachinventive dye in the liquid-crystalline state in wet aqueous gelatin,are largely retained in evaporated gelatin films or layers, and that insome cases the spectral features dramatically improve as excess water isremoved from the coating.

Example 7

Influence of Substituents on Spectral Properties of Coated Dyes.

Direct gelatin dispersions (DGD's) of Dyes 1-1A, 2-1A, 5-1 to 5-3, 6-1to 6-3 and Comparative Dyes A, B, E ancl F were prepared using powdereddye as described for Formulation B such that the wt % dye in each samplewas nominally 0.06-0.10%. Aliquots of each dispersion, held at 39° C.,were transferred to 0.0066 cm pathlength glass cells and theirabsorption spectra measured at 25° C. These samples are referred to as“Wet DGD's”. In addition, solution aliquots of each dispersion were alsosmeared onto standard glass microscope slides (0.8/1.0 mm thickness) toform uniformly thin wet films which were allowed to dry at ambienttemperature and humidity for at least 17 hours such that theirD_(max)(evap) was less than 4.0 absorbance units. These samples arereferred to as “evap DGD's”. For each dye, the absorbance maxima for themonomer band (λ_(Mmax)), and for the bathochromic band corresponding tothe liquid crystalline phase (λlc_(max)) were measured for both the “WetDGD's” and the “Evap. DGD's”, and the optical densities (O.D.) at theλ_(max) of the monomer band (O.D-M) and for the bathochromic bandcorresponding to the liquid crystal phase (O.D.-lc) were measured forboth the “Wet DCrD's” and the “Evap. DGD's”, then the ratios((O.D-lc)/(O.D-M)) were calculated. The results are shown in Table 22.

TABLE 22 λ M_(max) λ M_(max) (nm) λ 1c_(max) (nm) λ 1c_(max) Wet EvapWet Wet Evap Evap DGD DGD DGD DGD DGD DGD (O.D.-1c/ (O.d.-1c/ Dye (nm)(nm) (nm) (nm) O.D.-M) O.D.-M) 6-2 585 679 582 679 3.8 3.9 B2208 4 6-1600 681 600 683 8.0 8.0 B2165 5 6-3 610 683 610 688 6.6 6.5 B2213 4 5-1497 545 500 546 2.1 5.7 B2208 3 5-2 500 560 500 561 7.1 10.7 B- 232445-3 500 554 500 554 6.5 7.1 B2219 3 1-1A 455 489 450 488 2.6 4.6 B22550-T 2-1A 551 611 553 610 3.2 6.0 B2255 1-H F 589 none 606 none 0 0 E 497none 508 none 0 0 A 450 none 452 none 0 0 B 550 none 554 none 0 0

The above data clearly show that the presence or absence of hydrophobicsubstituents within a given dye class dramatically influence thepropensity of a dye to form a liquid crystalline phase. The data showsthat the inventive dyes are preferentially substituted as compared withthe comparative dyes to favor stable liquid crystal formation, and thatthe most preferred dyes have excellent ratios between the liquid crystaland monomer bands even in the wet melts (“Wet DGD's). Also, within thegroups of inventive dyes 5-1 to 5-3 and 6-1 to 6-3, liquid crystal phaseproperties are improved for the dyes bearing phenyl, benzo or chlorosubstituents relative to the unsubstituted analogs. The optimal balancebetween hydrophilic and hydrophobic groups will differ somewhat betweendye classes.

Example 8

Spectral Properties of Dried Gelatin Layers Containing Dyes FormulatedUsing Formulation A (SPD milling) and Formulation B (DGD) Procedures.

Direct gelatin dispersions of the Inventive Dyes 1-1, 1-1A and 2-1 wereprepared as described for FormulationB at concentrations equivalent todye laydowns of 0.064 g/m². Solution aliquots of each dispersion weresmeared onto glass microscope slides (0.8/1.0 mm thickness) to formuniformly thin wet films which were then allowed to dry at ambienttemperature and humidity for at least 17 hours. The absorption spectrafor these dried films were then measured at 25° C. These samples arereferred to in Table 23 as “Evap. DGD's”. The inventive dyes 1—1, 1-1Aand 2-1 were also dispersed in aqueous gelatin using the Formulation Aprocedure described for FormulationA. These dispersions were coated on apolyester support according to the following procedure. A spreadingagent (Olin 10G, an isononylphenoxy glycidol surfactand available fromOlin Corp.) and a hardener (bis(vinylsulfonylmethyl)ether) were added tothe dye-gelatin melt prepared as described above. A melt from thismixture was then coated on a poly(ethylene terephthalate) support toachieve a dye coverage of 0.043 to 0.129 g/m², a gelatin coverage of1.61 g/m², and a hardener level of 0.016 g/m². These samples arereferred to in Table 23 as “Evap SPD's”. The absorption spectrum of theevaporated coating was measured at 25° C. The data are summarized inTable 23.

TABLE 23 λ_(max) Evap Hbw Evap Hbw Evap DGD DGD λ_(max) Evap SPD SPD Dye(nm) (nm) (nm) (nm) 1-1 488 15 488 20 1-1A 487 14 488 22 2-1 610 19 61022

The data show no significant differences in λ_(max) or Hbw for the driedgelatin films containing the inventive liquid crystal-forming dyesformulated according to Formulation A (SPD)or Formulation B (DGD)procedures outlined in Examples A and B, respectively. Thus theadvantageous spectral properties of the inventive dyes in aliquid-crystalline state can be obtained using the simpler procedure(Formulation B) without the need to resort to the more complex millingprocedure (Formulation A) commonly used for solid particle dyes.

Example 9

Spectral Shape of Evaporated Dye DGD's.

Direct gelatin dispersions (DGD's) of Dyes 1-1 to I-5, 2-1 to 2-4, 3-1were prepared as described for FormulationB. Solution aliquots of eachdispersion were also smeared onto standard glass microscope slides(0.8/1.0 mm thickness) to form uniformly thin wet films which wereallowed to dry at ambient temperature and humidity for at least 17 hourssuch that their D_(max)(evap) was less than 2.5 absorbance units. Theabsorbance spectrum for each coated DGD was measured. Comparative solidparticle dyes D, G, H, I, J and K were prepared as described forFormulationA. Melts for each comparative dye was then coated on apoly(ethylene terephthalate) support to achieve a dye coverage of 0.043to 0.129 g/m², a gelatin coverage of 1.61 g/m², and a hardener level of0.016 g/m². The absorption maxima and halfbaridwidths (Hbw) of the driedcoatings were measured at 25° C. The ratio of each dye's optical densityat λ_(max)(D_(max)) to optical density (O.D.) at λ_(max)+20 nm wascalculated. The ratio of each dye's optical density at λ_(max)(D_(max))to optical density (O.D.) at λ_(max)−20 nm was also calculated. Theseratios are a measure of spectral band sharpness. Dyes with higher ratiospossess sharper cutting spectral absorption envelopes which aredesirable for light filtration/absorption applications. The data aresummarized in Table 24.

TABLE 24 λ_(max) HBW D_(max)/O.D. at D_(max)/O.D. at Dye (nm) (nm)λ_(max+20 nm) λ_(max−20 nm)  1-1A 487 14 >20 3.36  1-2 476 13 >20 2.3 1-2A 477 13 >20 3.0  1-3 483 14 >20 2.1  1-4 486 21 >20 2.3  1-5 47619 >20 2.5  2-1 610 19 >20 3.5  2-1A 610 21 >20 1.8  2-3 610 18 >20 3.2 2-4 609 15 >20 7.2  2-6 624 12 >20 2.3  3-1 487 24 2.5 4.4  5-2 561 1916.1 3.6  5-3 553 22 16.1 2.9  5-4 554 24 >20 6.4  5-6 555 17 10.1 3.1 5-15 599 31 7.6 1.9  5-16 616 24 19.3 0.8  5-27 612 20 15.7 3.5  6-1684 24 >20 2.0  6-3 666 46 1.9 1.5  6-4 670 31 6.0 2.1  6-5 684 36 4.01.9  6-13 682 27 8.8 2.2  7-1 472 12 3.5 7.8 10-10 454 19 10.9 2.4 11-4477 19 >20 2.8 12-4 637 21 15.2 3.3 13-1 630 20 >20 3.3 13-5 641 14 >202.3 15-1 552 20 >20 3.3 D 676 102 1.8 1.34 G 476 110 1.2 1.05 H 654 2001.2 1.16 I 446 93 1.2 1.29 J 538 130 1.1 1.04 K 432 100 1.1 1.12

The data clearly demonstrate that the inventive liquid crystal-formingdyes when coated in aqueous gelatin coatings possess absorption spectrawith significantly narrower absorbance envelopes and exhibit sharperhypsochromic and bathochromic edges relative to the comparative solidparticle dyes. It should also be noted that for the inventive dyes withratios marked as “>20”, the O.D+20 nm value is sufficiently low that ithas no measurable density relative to noise. It should also be notedthat when the comparative dyes were formulated using Formulation B, thequality of the resulting coatings was very poor due to the insolubilityof the dyes in the melts. The comparative dyes were therefore milled(Formulation A) prior to coating, as is the usual procedure for solidparticle dyes. Therefore, the dyes of this invention not only possessspectral properties far superior to the comparative examples, but theirsuperior properties may be obtained without requiring the more complexFormulation A procedure by instead using the simple Formulation Bprocedure.

This example demonstrates a fundamental advantage of the inventiveliquid crystal-forming dyes over solid particle dyes. This example alsodemonstrates that the inventive liquid crystalline dyes provide sharp,narrowly absorbing spectra in coatings that are virtually unachievableusing traditional solid particle dyes.

Example 10

Covering Power of Liquid Crystalline Dyes Versus Solid Particle(microcrystalline) Analogs

Melts of Dyes 1-1, 2-1 were prepared as described for FormulationB.Melts for Comparative Dyes D, J and K were prepared as described asdescribed for FormulationA. (Formulation A was used for themicrocrystalline comparative dyes for the same reasons cited in theprevious example). Melts for each dye were then coated on apoly(ethylene terephthalate) support to achieve a dye coverage of 0.043to 0.129 g/m², a gelatin coverage of 1.61 g/m², and a hardener level of0.016 g/m². The absorption of the dried coatings were measured at 25° C.The covering power for each of the coated dyes was calculated bydividing the optical density (O.D.) at λ_(max) by the dye laydown inmg/ft2. The data are summarized in Table 25.

TABLE 25 λ_(max) coating Covering power of coated Dye (nm) dye 1-1 4880.23 2-1 610 0.48 D 670 0.11 J 538 0.15 K 432 0.09

It is clear from the above data that coated inventive dyes possess farsuperior covering power relative to those of the comparative solidparticle dyes. It is also evident from this data that the inventiveliquid crystalline dyes allow for much smaller quantities of coatedmaterials to be used to achieve a required optical density level atD_(max) versus those of the comparative dyes. This example demonstratesanother fundamental advantage of the inventive liquid crystal-formingdyes over solid particle dyes. This example also demonstrates that theinventive liquid crystalline dyes provide sharp, narrowly absorbingspectra in coatings that are virtually unachieveable by traditionalsolid particle dyes.

Example 11

Process Removability of Dyes

The inventive Dyes 1—1, 1-1A, 1-2, 1-2A, and 2-1 were formulatedaccording to Formulation B. These dye dispersions were coated on apolyester support according to the following procedure. A spreadingagent (surfactant 10 G) and a hardener (bis(vinylsulfonylmethyl)ether)were added to the dye-gelatin melt prepared as described above. A meltfrom this mixture was then coated on a poly(ethylene terephthalate)support to achieve a dye coverage of 0.043 to 0.161 g/m², a gelatincoverage of 1.61 g/m², and a hardener level of 0.016 g/m². Theabsorption spectrum of the dried coating was measured at 25° C.Identical elements were subjected to Kodak E-6® processing (which isdescribed in British Journal of Photography Annual, 1977, pp. 194-97)and the absorbance was measured for each. The results are shown in Table26.

TABLE 26 λ_(max)SPD_(dry) D_(max) Dye (nm) D_(max) after E-6 Processing1-1 488 >1.0 0.0 1-1A 488 >1.0 0.0 1-2 476 >1.0 0.0 1-2A 476 >1.0 0.02-1 610 >2.0 0.0

In spite of the inordinately high optical densities (D_(max)'s) for suchlow dye laydowns of the liquid crystal-forming coated dyes, no residualdeleterious dye stain (optical density) could be detected afterprocessing.

Example 12

Thermal Stability

The inventive Dyes 1-1, 1-1A, 2-1 and 2-1A were formulated using theFormulation B and coated on a polyester support as outlined in Example11. Each dye was coated at a laydown such that the measured D_(max) wasless than 2.0. For each example, the absorbance spectrum for the dyedgelatin coating was measured both before and after incubation for sevendays at 120° C./50% relative humidity. The results are summarized inTable 27.

TABLE 27 D_(max) SPD Dye laydown λ_(max) SPD before D_(max) SPD afterDye (g/m²) (nm) incubation incubation 1-1 0.043 488 0.9 0.9 1-1A 0.043488 0.6 0.6 2-1 0.129 610 1.9 1.8

It is clear from the data that the liquid crystal-forming dyes in theinventive examples show an excellent robustness toward high heat andhumidity as evidenced by the fact that little or no density loss at thebathochromic λ_(max) is observed as a result of incubation. Furthermore,the absence of any detectable optical density at the monomeric λ_(max)of the inventive dyes following incubation demonstrates that little orno mobile monomeric dye species is produced under these conditions.Consequently, the inventive dyes in the liquid-crystalline state exhibitexcellent robustness and fastness to diffusion at high temperature andhumidity.

In summary, the above examples demonstrate that the inventive dyessuccessfully solve the problems inherent in the filter dyes of the priorart. Soluble dyes typically migrate in coatings unless mordanted. Solidparticle dyes typically do not migrate, but their spectral envelopes aregenerally very broad, low in covering power, and not sharp-cutting.Furthermore, solid particle dyes require specialized milling procedure,for incorporation into coated elements. Our examples demonstrate thatour inventive liquid crystal-forming dyes possess the combination ofsuperior spectral characteristics of high extinction, narrow bandwidth,and sharp-cutting edges and furthermore remain immobile and thereforeallow layer-specific dyeing without the use of mordants. Moreover, manyof the liquid crystal-forming dyes of this invention are readilydecolorized or removed from the photographic element upon processing,leaving little or no post-process dye stain.

The invention has been described in detail with particular reference topreferred embodiments, but it will be understood that variations andmodifications can be effected within the spirit and scope of theinvention.

What is claimed is:
 1. A photographic element comprising a supportbearing at least one light sensitive silver halide emulsion layer and atleast one light insensitive layer, wherein said light insensitive layercomprises a dispersion comprising a solvent having dispersed therein aliquid-crystal forming dye of structural Formula I:[D-(X)_(m)]-(Y)_(n)  I wherein: D is a light-absorbing chromophore otherthan a cyanine dye or a barbituric acid or thiobarbitlric acid oxonoldye; each Y contains an ionic or a nonionic solubilizing substituent ora group with a pKa value of less than 4 in water; each X is a nonionicsubstituent; n is 0 to 10; m is 0-10; and the resulting dye forms alyropic liquid-crystalline phase in solvent.
 2. A photographic elementaccording to claim 1, wherein the solvent is water or an aqueous mediumcontaining a hydrophilic colloid.
 3. A photographic element according toclaim 2, wherein the hydrophilic colloid is gelatin.
 4. A photographicelement according to claim 1, wherein D is derived from an arylidenedye, an oxonol dye, a merocyanine dye, a styryl dye, a coumarin dye, anazo dye, a hemioxonol dye, a metal-chelated dye, a triarylmethane dye,an indoaniline dye, a chalcone dye, an anthraquinone dye, or a butadienedye.
 5. A photographic element according to claim 1, wherein Y iscarboxylate, sulfo, sulfato, sulfate, phosphate, phosphonate,trialkylammonium, pyiidinium, alkylpyridinium hydroxylate, enolate,dibcyanovinylate, alkyl ether, zwittenonic group or a group with a pKavalue below
 4. 6. A photographic element according to claim 1, wherein Yis sulfonic acid, acylsulfonamide, a saccaiin moiety orsulfonylsufonamido.
 7. A photographic element according to claim 1,wherein Y is a nonionic solubilizing group.
 8. A photographic elementaccording to claim 1, wherein X is ai-yl, alkyl, aralkyl, halogen,cycloalkyl, alkoxy, alkylamino, acyl, carboxy, carboxyalkyl, sulfonamidoor alkylthio.
 9. A photographic element according to claim 1, whereinthe dye is of Formula II:

wherein A¹ and A² are ketomethylene or activated methylene moieties,L¹-L⁷ each independently represent a substituted or unsubstitutedmethine group, M⁺ is a cation, and p, q and r are independently 0 or 1.10. A photographic element according to claim 9, wherein the dye is ofFormula IIa or Formula IIb:

wherein W¹ and Y¹ are the atoms required to form a cyclic activatedmethylene/ketomethylene moiety; R¹ and R³ are aromatic or heteroaromaticgroups; R² and R⁴ are electron-withdrawing groups; G is O ordicyanovinyl (—C(CN)₂)) and p, q and r are independently 0 or 1, andL¹-L⁷ each represent a substituted or unsubstituted methine groups. 11.A photographic element according to claim 1, wherein the dye is ofFormula IV:

wherein A³ is a ketomethylene or activated methylene moiety; L⁸-L¹⁵ eachindependently represents a substituted or unsubstituted methine group,Z¹ represents the non-metallic atoms necessary to complete a substitutedor unsubstituted ring system containing at least one 5 or 6-memberedheterocyclic nucleus; R¹⁷ represents a substituted or unsubstitutedalkyl, aryl, or aralkyl group; with the proviso that at least onesubstituent on the dye of Formula IV contains a ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water. 12.A photographic element according to claim 1, wherein the dye is ofFormula VI:

wherein A⁵ is a ketomethylene or activated methylene, L¹⁶ through L¹⁸each independently represent a substituted or unsubstituted methine, R³¹is alkyl, aryl or aralkyl, Q3 represents the non-metallic atomsnecessary to complete a substituted or unsubstituted ring systemcontaining at least one 5- or 6-membered heterocyclic nucleus, each R³²group independently represents hydrogen, alkyl, cycloalkyl, alkenyl,substituted or unsubstituted aryl, heteroaryl or aralkyl, alkylthio,hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen, cyano, nitro,carboxy, acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl,including the atoms required to form fused aromatic or heteroaromaticrings, or a group containing a solubilizing substituent, y is 0, 1, 2, 3or 4, z is 0, 1 or 2; with the proviso that at least one substituent onthe dye of Formula VI contains an ionic or non-ionic solubilizing groupor a group with a pKa value less than 4 in water.
 13. A photographicelement according to claim 1, wherein the dye is of Formula VII:

wherein A⁶ is a ketomethylene or activated methylene, L¹⁶ through L¹⁸each independently represents a substituted or unsubstituted methinegroup, R³³ is substituted or unsubstituted alkyl, aryl or aralkyl group,R³⁴ is substituted or unsubstituted aryl, alkyl or aralkyl group, eachR³⁵ group independently represents hydrogen, alkyl, cycloalkyl,alkeneyl, substituted or unsubstituted aryl, heteroaryl or aralkyl,alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen,cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido,sulfamoyl, including the atoms required to form fused aromatic orheteroaromatic rings, or groups containing a solubilizing substituent, zis 0, 1 or 2, and a is 0, 1, 2, 3 or 4; with the proviso that at leastone substituent on the dye of Formula VII contains an ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water. 14.A photographic element according to claim 1, wherein the dye is ofFormula VIII:

wherein A⁷ represents a ketomethylene or activated methylene moiety, L¹⁹through L²¹ each independently represents a substituted or unsubstitutedmethine group, each R36 group independently represents hydrogen, alkyl,cycloalkyl, alkeneyl, substituted or unsubstituted aryl, heteroaryl oraralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino,halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing a solubilizingsubstiituent, b represents 0 or 1, and c represents 0, 1, 2, 3 or 4;with the proviso that at least one substituent on the dye of FormulaVIII is a ionic or non-ionic solubilizing group or a group with a pKavalue less than 4 in water.
 15. A photographic element according toclaim 1, wherein the dye is of Formula IX:

wherein A⁸ is a ketomethylene or activated methylene, L¹⁹ through L²¹each independently represent a substituted or unsubstituted methinegroup, b is 0 or 1, each R³⁹ group independently represents hydrogen,alkyl, cycloalkyl, alkeneyl, substituted or unsubstituted aryl,heteroaryl or aralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino,alkylamino, halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl,aminocarbonyl, sulfonamido, sulfamoyl, including the atoms required toform fused aromatic or heteroaromatic rings, or groups containing asolubilizing substituent, and R37 and R³⁸ each independently representssubstituted or unsubstituted aryl, alkyl or aralky, and d represents 0,1, 2, 3 or 4; with the proviso that at least one substituent on the dyeof Formula IX is a ionic or non-ionic solubilizing group or a group witha pKa value less than 4 in water.
 16. A photographic element accordingto claim 1, wherein the dye is of Formula X:

wherein A⁹ is a ketomethylene or activated methylene moiety, L²² throughL²⁴ each represents a substituted or unsubstituted methine group, e is 0or 1, each R⁴⁰ group independently represents hydrogen, alkyl,cycloalkyl, alkeneyl, substituted or unsubstituted aryl, heteroaryl oraralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino,halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing a solubilizingsubstituent, and f is 0, 1, 2, 3 or 4; with the proviso that at leastone substituent on the dye of Formula X contains an ionic or non-ionicsolubilizing group or a group with a pKa value less than
 4. 17. Aphotographic element according to claim 1, wherein the dye is of FormulaXI:

wherein A¹⁰ is a ketomethylene or activated methylene moiety, L²⁵through L²⁷ each independently represents a substituted or unsubstitutedmethine group, g is 0, 1 or 2, and R³⁷ and R³⁸ each independentlyrepresents substituted or unsubstituted aryl, alkyl or aralky; with theproviso that at least one substituent on the dye of Formula XI containsan ionic or non-ionic solubilizing group or a group with a pKa valueless than
 4. 18. A photographic element according to claim 1, whereinthe dye is of Formula XII:

wherein A¹¹ is a ketomethylene or activated methylene moiety, each R⁴¹group independently represents hydrogen, alkyl, cycloalkyl, alkeneyl,substituted or unsubstituted aryl, heteroaryl or aralkyl, alkylthio,hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen, cyano, nitro,carboxy, acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl,including the atoms required to form fused aromatic or heteroaromaticrings, or groups containing a solubilizing substituent, R³⁷ and R³⁸ eachrepresents substituted or unsubstituted aryl, alkyl or aralky, and h is0, 1, 2, 3, or 4; with the proviso that at least one substituent on thedye of Formula XII contains an ionic or non-ionic solubilizing group ora group with a pKa value less than 4 in water.
 19. A photographicelement according to claim 1, wherein the dye is of Formula XIII:Q⁴—N═N—Q⁵  Formula XIII wherein Q⁴ and Q⁵ each represents the atomsnecessary to form at least one heterocyclic or carbocyclic, fused orunfused 5 or 6-membered-ring conjugated with the azo linkage; with theproviso that at least one substituent on the dye of Formula XII containsan ionic or non-ionic solubilizing group or a group with a pKa valueless than
 4. 20. An imaging element other than a photographic elementcontaining a light sensitive silver halide emulsion layers, saidcontaining a dispersion comprising a solvent having dispersed therein aliquid-crystal forming dye of structural Formula I:[D-(X)_(m)]-(Y)_(n)  I wherein: D is a light-absorbing chromophore otherthan a cyanine dye or a barbituric acid or thiobarbituric acid oxonoldye; each Y contains an ionic or a nonionic solubilizing substituent ora group with a pKa value of less than 4 in water; each X is a nonionicsibstituent; n is 0 to 10; m is 0-10; and the resulting dye forms alyotic liquid-crystalline phase in solvent.
 21. A imaging elementaccording to claim 20, wherein the solvent is water or an aqueous mediumcontaining a hydrophilic colloid.
 22. A imaging element according toclaim 21, wherein the hydrophilic colloid is gelatin.
 23. A imagingelement according to claim 20, wherein D is derived from an arylidenedye, an oxonol dye, a merocyanine dye, a styryl dye, a coumarin dye, anazo dye, a hemioxonol dye, a metal-chelated dye, a triarylmethane dye,an indoaniline dye, a chalcone dye, an anthraquinone dye, or a butadienedye.
 24. A imaging element according to claim 20, wherein Y iscarboxylate, sulfo (SO₃ ⁻), sulfato, sulfate, phosphate, phosphonate,trialkylammonium, pyridinium, alkylpyridinium, hydroxylate, enolate,dicyanovinylate, alkyl ether, zwitterionic group or a group with a pKavalue below
 4. 25. A imaging element according to claim 20, wherein Y issulfonic acid, acylsulfonamide, a saccarin moiety orsulfonylsulfonamido.
 26. A imaging element according to claim 20,wherein Y is a nonionic solubilizing group.
 27. A imaging elementaccording to claim 20, wherein X is alkyl, alkyl, aralkyl, halogen,cycloalkyl, alkoxy, alkylamino, acyl, carboxy, carboxyalkyl, sulfonamidoor alkylthio.
 28. A imaging element according to claim 20, wherein thedye is of Formula II:

wherein A¹ and A² are ketomethylene or activated methylene moieties,L¹-L⁷ each independently represent a substituted or unsubstitutedmethine group, M⁺ is a cation, and p, q and r are independently 0 or 1.29. A imaging element according to claim 28, wherein the dye is ofFormula IIa or Formula IIb:

wherein W¹ and Y¹ are the atoms required to form a cyclic activatedmethylene/ketomethylene moiety; R¹ and R³ are aromatic or heteroaromaticgroups; R² and R⁴ are electron-withdrawing groups; G³ is O ordicyanovinyl (—C(CN)₂)) and p, q and r are independently 0 or 1, andL¹-L⁷ each represent a substituted or unsubstituted methine groups. 30.A imaging element according to claim 20, wherein the dye is of FormulaIV:

wherein A³ is a ketomethylene or activated methylene moiety; L⁸-L¹⁵ eachindependently represents a substituted or unsubstituted methine group,Z1 represents the non-metallic atoms necessary to complete a substitutedor unsubstituted ring system containing at least one 5 or 6-memberedheterocyclic nucleus; R¹⁷ represents a substituted or unsubstitutedalkyl, aryl, or aralkyl group; with the proviso that at least onesubstituent on the dye of Formula IV contains a ionic or non-ionicsolubilizing group or a group with a pKa value less than 4 in water. 31.A imaging element according to claim 20, wherein the dye is of FormulaVI:

wherein A⁵ is a ketomethylene or activated methylene, L¹⁶ through L¹⁸each independently represent a substituted or unsubstituted methine, R³¹is alkyl, aryl or aralkyl, Q3 represents the non-metallic atomsnecessary to complete a substituted or unsubstituted ring systemcontaining at least one 5- or 6-membered heterocyclic nucleus, each R³²group independently represents hydrogen, alkyl, cycloalkyl, alkenyl,substituted or unsubstituted aryl, heteroaryl or aralkyl, alkylthio,hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen, cyano, nitro,carboxy, acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl,including the atoms required to form fused aromatic or heteroaromaticrings, or a group containing a solubilizing substituent, y is 0, 1, 2, 3or 4, z is 0, 1 or 2; with the proviso that at least one substituent onthe dye of Formula VI contains an ionic or non-ionic solubilizing groupor a group with a pKa value less than 4 in water.
 32. A imaging elementaccording to claim 20, wherein the dye is of Formula VII:

wherein A⁶ is a ketomethylenc or activated methylene, L¹⁶ through L¹⁸each independently represents a substituted or unsubstituted methinegroup, R³³ is substituted or unsubstituted alkyl, aryl or aralkyl group,R³⁴ is substituted or unsubstituted aryl, alkyl or aralkyl group, eachR³⁵ group independently represents hydrogen, alkyl, cycloalkyl,alkeneyl, substituted or unsubstituted aryl, heteroaryl or aralkyl,alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen,cyano, nitro, carboxy, acyl, alk.oxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing a solubilizingsubstituent, z is 0, 1 or 2, and a is 0, 1, 2, 3 or 4; with the provisothat at least one substituent on the dye of Formula VII contains anionic or non-ionic solubilizing group or a group with a pKa value lessthan 4 in water.
 33. A imaging element according to claim 20, whereinthe dye is of Formula VIII:

wherein A⁷ represents a ketomethylene or activated methylene moiety, L¹⁹through L²¹ each independently represents a substituted or unsubstitutedmethine group, each R³⁶ group independently represents hydrogen, alkyl,cycloalkyl, alkeneyl, substituted or unsubstituted aryl, heteroaryl oraralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, am.nino, alkylamino,halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing a solubilizingsubstituent, b represents 0 or 1, and c represents 0, 1, 2, 3 or 4; withthe proviso that at least one substituent on the dye of Formula VIII isa ionic or non-ionic solubilizing group or a group with a pKa value lessthan 4 in water.
 34. A imaging element according to claim 20, whereinthe dye is of Formula IX:

wherein A⁸ is a ketomethylene or activated methylene, L¹⁹ through L²¹each independently represent a substituted or unsubstituted methinegroup, b is 0 or 1, each R³⁹ group independently represents hydrogen,alkyl, cycloalkyl, alkeneyl, substituted or unsubstituted aryl,heteroaryl or aralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino,alkcylamino, halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl,aminocarbonyl, sulfonamido, sulfamoyl, including the atoms required toform fused aromatic or heteroaromatic rings, or groups containing asolubilizing substituent, and R³⁷ and R³⁸ each independently representssubstituted or unsubstituted aryl, alkyl or aralky, and d represents 0,1, 2, 3 or 4; with the proviso that at least one substituent on the dyeof Formula IX is a ionic or non-ionic solubilizing group or a group witha pKa value less than 4 in water.
 35. A imaging element according toclaim 20, wherein the dye is of Formula X:

wherein A⁹ is a ketomethylene or activated methylene moiety, L²² throughL²⁴ each represents a substituted or unsubstituted methine group, e is 0or 1, each R40 group independently represents hydrogen, alkyl,cycloalkyl, alkeneyl, substituted or unsubstituted aryl, heteroaryl oraralkyl, alkylthio, hydroxy, hydroxylate, alkoxy, amino, alkylamino,halogen, cyano, nitro, carboxy, acyl, alkoxycarbonyl, aminocarbonyl,sulfonamido, sulfamoyl, including the atoms required to form fusedaromatic or heteroaromatic rings, or groups containing a solubilizingsubstituent, and f is 0, 1, 2, 3 or 4; with the proviso that at leastone substituent on the dye of Formula X contains an ionic or non-ionicsolubilizing group or a group with a pKa value less than
 4. 36. Aimaging element according to claim 20, wherein the dye is of Formula XI:

wherein A¹⁰ is a ketomethylene or activated methylene moiety, L²⁵through L²⁷ each independently represents a substituted or unsubstitutedmethine group, g is 0, 1 or 2, and R³⁷ and R³⁸ each independentlyrepresents substituted or unsubstituted aryl, alkyl or aralky; with theproviso that at least one substituent on the dye of Formula XI containsan ionic or non-ionic solubilizing group or a group with a pKa valueless than
 4. 37. A imaging element according to claim 20, wherein thedye is of Formula XII:

wherein A¹¹ is a ketomethylene or activated methylene moiety, each R⁴¹group independently represents hydrogen, alkyl, cycloalkyl, alkeneyl,substituted or unsubstituted aryl, heteroaryl or aralkyl, alkylthio,hydroxy, hydroxylate, alkoxy, amino, alkylamino, halogen, c yano, nitro,carboxy, acyl, alkoxycarbonyl, aminocarbonyl, sulfonamido, sulfamoyl,including the atoms required to form fused aromatic or heteroaromaticrings, or groups containing a solubilizing substituent, R³⁷ and R³⁸ eachrepresents substituted or unsubstituted aryl, alkyl or aralky, and h is0, 1, 2, 3, or 4; with the proviso that at least one substituent on thedye of Formula XII contains an ionic or non-ionic solubilizing group ora group with a pKa value less than 4 in water.
 38. A imaging elementaccording to claim 20, wherein the dye is of Formula XIII:Q⁴—N═N—Q⁵  Formula XIII wherein Q⁴ and Q⁵ each represents the atomsnecessary to form at least one heterocyclic or carbocyclic, fused orunfused 5 or 6-membered-ring conjugated with the azo linkage; with theproviso that at least one substituent on the dye of Formula XIIIcontains an ionic or non-ionic solubilizing group or a group with a pKavalue less than 4.